ADTRAN Network Card ISU 128 User Manual
ISU 128  
128 kbps ISDN Service Unit  
USER MANUAL  
Part Numbers  
1202029L2  
1202029L3  
115 VAC  
115 VAC with V.34 Modem Option  
61202.029L2-1D  
January 1998  
 
FCC regulations require that the following information be provided to the custom-  
er in this manual.  
1. If your telephone equipment ( ISU 128) causes harm to the telephone network, the  
telephone company may discontinue your service temporarily. If possible, they  
will notify you in advance. But if advance notice isn’t practical, you will be notified  
as soon as possible. You will be advised of your right to file a complaint with the  
FCC.  
2. Your telephone company may make changes in its facilities, equipment, operations,  
or procedures that could affect the proper operation of your equipment. If they do,  
you will be given advance notice so as to give you an opportunity to maintain unin-  
terrupted service.  
3. If you experience trouble with this equipment ( ISU 128), please contact ADTRAN  
(see inside back cover) for repair/warranty information. The telephone company  
may ask you to disconnect this equipment from the network until the problem has  
been corrected, or until you are sure the equipment is not malfunctioning.  
4. This unit contains no user-serviceable parts.  
To ADTRAN service personnel: For continued protection against risk of fire, re-  
place F1 with the same type and rating of fuse only: .2 A, 250 V.  
 
FEDERAL COMMUNICATIONS COMMISSION  
RADIO FREQUENCY INTERFERENCE STATEMENT  
FCC ID: HDC1202029TL  
This equipment has been tested and found to comply with the limits for a Class B dig-  
ital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide  
reasonable protection against harmful interference in a residential environment. This  
equipment generates, uses, and can radiate radio frequency energy and, if not installed  
and used in accordance with the instructions, may cause harmful interference to radio  
or TV reception, which can be determined by turning the equipment off and on. The  
user is encouraged to try to correct the interference by one or more of the following  
measures:  
• Reorient or relocate the receiving antenna.  
• Increase the separation between the equipment and receiver.  
• Connect the equipment into an outlet on a circuit different from that to  
which the receiver is connected.  
• Consult the dealer or an experienced radio/TV technician for help.  
This device is FCC Class B certified only on the EIA-232 interface. The  
V.35 and RS-530 interfaces are FCC Class B verified.  
Changes or modifications not expressly approved by ADTRAN will void  
the user’s authority to operate this equipment.  
 
CANADIAN EMISSIONS REQUIREMENTS  
This digital apparatus does not exceed the Class B limits for radio noise emissions from  
digital apparatus as set out in the interference-causing equipment standard entitled  
"Digital Apparatus," ICES-003 of the Department of Communications.  
Cet appareil nuerique respecte les limites de bruits radioelectriques applicables aux  
appareils numeriques de Class B prescrites dans la norme sur le materiel brouilleur:  
"Appareils Numeriques," NMB-003 edictee par le ministre des Communications.  
CANADIAN EQUIPMENT LIMITATIONS  
Notice: The Canadian Industry and Science Canada label identifies certified equip-  
ment. This certification means that the equipment meets certain telecommunications  
network protective, operational, and safety requirements. The Department does not  
guarantee the equipment will operate to the user’s satisfaction.  
Before installing this equipment, ensure that it is permissible to be connected to the fa-  
cilities of the local telecommunications company. The equipment must also be in-  
stalled using an acceptable method of connection. In some cases, the company’s inside  
wiring associated with a single-line individual service may be extended by means of a  
certified connector assembly (telephone extension cord). Compliance with the above  
conditions may not prevent degradation of service in some situations.  
Repairs to certified equipment should be made by an authorized Canadian mainte-  
nance facility designated by the supplier. Any repairs or alterations made by the user  
to this equipment, or equipment malfunctions, may give the telecommunications com-  
pany cause to request the user to disconnect the equipment.  
Users should ensure for their own protection that the electrical ground connections of  
the power utility, telephone lines, and internal metallic water pipe system, if present,  
are connected together. This precaution may be particularly important in rural areas.  
Users should not attempt to make such connections themselves, but should contact the  
appropriate electric inspection authority, or an electrician, as appropriate.  
The Load Number (LN) assigned to each terminal device denotes the percentage of the  
total load to be connected to a telephone loop which is used by the device, to prevent  
overloading. The termination on a loop may consist of any combination of devices  
subject only to the requirement that the total of the Load Numbers of all devices does  
not exceed 100.  
 
Table of Contents  
Chapter 1. Understanding ISDN and the ISU 128 ..................................................... 1  
ISDN Overview .................................................................................................................. 1  
The ADTRAN ISU 128....................................................................................................... 1  
ISU 128 Interoperability .................................................................................................... 4  
Recommended Operating Protocols................................................................................ 6  
Chapter 2. ISDN Ordering Codes (IOCs)..................................................................... 9  
Ordering ISDN using IOCs............................................................................................... 9  
Capability S ......................................................................................................................... 10  
Applications.......................................................................................................... 10  
Capability R.................................................................................................................. 10  
Applications.......................................................................................................... 10  
Capability B .................................................................................................................. 10  
Capability C.................................................................................................................. 10  
Chapter 3. Installation..................................................................................................... 11  
Network Connection.......................................................................................................... 11  
DTE Data Connection........................................................................................................ 12  
Dial Interface Connection.................................................................................................. 12  
Maintenance Interface ....................................................................................................... 13  
Chapter 4. Operation ....................................................................................................... 15  
Menu Navigation ............................................................................................................... 15  
Getting Started.................................................................................................................... 16  
Status Buffer ................................................................................................................. 16  
VT 100 Terminal Menu Support ...................................................................................... 17  
Status Screen................................................................................................................. 17  
Configuration Screen .................................................................................................. 18  
Chapter 5. Testing ............................................................................................................ 19  
TEST Options ...................................................................................................................... 19  
Loopback DTE.............................................................................................................. 20  
Loopback Network...................................................................................................... 20  
Loopback Protocol....................................................................................................... 20  
Loopback Remote ........................................................................................................ 21  
Test Remote .................................................................................................................. 21  
Loopback Disable ........................................................................................................ 21  
No Remote Loopbacks.................................................................................. 21  
DDS Accepted................................................................................................ 21  
V.54 Accepted ................................................................................................ 21  
DDS+V54 Accept........................................................................................... 22  
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Table of Contents  
Near-End Block Errors/Far-End Block Errors (NEBE/FEBE).............................. 22  
Software Version.......................................................................................................... 22  
Chapter 6. Configuration ................................................................................................. 23  
Dial Line Operation............................................................................................................ 23  
Switch Protocol ............................................................................................................ 24  
Call Type....................................................................................................................... 24  
Speech.................................................................................................................... 24  
Audio ..................................................................................................................... 25  
Data 56 kbps.......................................................................................................... 25  
Data 64 kbps (default) ......................................................................................... 25  
Terminal Identification ............................................................................................... 25  
Setting the SPID.................................................................................................... 25  
Setting the LDN.................................................................................................... 26  
Dial Options.................................................................................................................. 29  
Front Panel............................................................................................................ 29  
RS-366 .................................................................................................................... 29  
1 sec or EON................................................................................................... 30  
2 sec or EON................................................................................................... 30  
5 sec or EON (default)................................................................................... 30  
10 sec or EON................................................................................................. 30  
20 sec or EON................................................................................................. 30  
Wait for EON ................................................................................................. 30  
AT Commands ............................................................................................................. 30  
Using AT Commands ................................................................................... 31  
Using S-Registers........................................................................................... 31  
Reading S-Registers....................................................................................... 32  
Reading S-Register Strings........................................................................... 32  
Changing S-Registers.................................................................................... 32  
Changing S-Register Strings ........................................................................ 32  
Dialing a Call Using the AT Command Processor ................................... 32  
V.25 bis .......................................................................................................................... 33  
V.25 ASYNC Dialing..................................................................................... 34  
V.25 SYNC HDLC Dialing ........................................................................... 35  
V.25 SYNC BISYNC Dialing ...................................................................... 35  
V.25 HDLC FLAG.......................................................................................... 35  
Disabled................................................................................................................. 35  
Auto Answer ................................................................................................................ 36  
Disabled................................................................................................................. 36  
Enabled.................................................................................................................. 36  
Dump all calls....................................................................................................... 36  
Answer Tone ................................................................................................................ 37  
No Answer Tone (Default) ................................................................................. 37  
Incoming Tone...................................................................................................... 37  
Outgoing Tone...................................................................................................... 37  
Always Tone ......................................................................................................... 37  
Connect Timeout.......................................................................................................... 38  
Call Screening............................................................................................................... 38  
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Leased Line Service............................................................................................................ 40  
Clock Mode: Slave/Master ....................................................................................... 40  
Channel rate ................................................................................................................. 41  
DTE OPTIONS.................................................................................................................... 42  
Bit Rate .......................................................................................................................... 42  
Connector Type............................................................................................................ 43  
RTS Options.................................................................................................................. 43  
CTS Options ................................................................................................................. 43  
CD Options................................................................................................................... 43  
DTR Options................................................................................................................. 43  
DSR Options................................................................................................................. 44  
Flow Control (Asynchronous Data Format)............................................................ 44  
Data Format (Asynchronous) .................................................................................... 45  
Transmit Clock (Synchronous Data Format)........................................................... 45  
Chapter 7. Protocol Options............................................................................................ 47  
Protocol Options................................................................................................................. 47  
Clear Channel............................................................................................................... 48  
BONDING Mode 1...................................................................................................... 48  
TXINIT ............................................................................................................ 49  
TXFA ............................................................................................................... 49  
TXADD01 ....................................................................................................... 50  
TXDEQ............................................................................................................ 50  
TANULL......................................................................................................... 50  
TCID................................................................................................................ 50  
V.120 .............................................................................................................................. 50  
V.110 .............................................................................................................................. 51  
V.34 ................................................................................................................................ 51  
Error Control.................................................................................................. 51  
Compression .................................................................................................. 52  
Microcom™ Network Protocol Block Size (MNP® Blk) ......................... 52  
DSU 57.6 ASYNC......................................................................................................... 53  
T-Link............................................................................................................................ 53  
Simple ADTRAN Protocol (SAP).............................................................................. 53  
FALLBACK .................................................................................................................. 54  
Point-to-Point (PPP) Async-to-Sync ......................................................................... 56  
Point-to-Point Protocol (PPP)............................................................................. 56  
Multilink Point-to-Point Protocol (MP)............................................................ 56  
PPP with Compression ....................................................................................... 57  
Chapter 8. Quick Setup.................................................................................................... 59  
Quick Setup Configuration............................................................................................... 59  
Quick Setup .................................................................................................................. 60  
Dial 56K sync* ...................................................................................................... 60  
Dial 64K sync* ...................................................................................................... 61  
Dial 112K sync* .................................................................................................... 61  
Dial 128K sync* .................................................................................................... 62  
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Table of Contents  
Dial PPP* ............................................................................................................... 62  
V34 115.2 async*................................................................................................... 63  
Dial 57.6 asyn* ...................................................................................................... 63  
Dial 115.2 asyn* .................................................................................................... 64  
Fallback 57.6k*...................................................................................................... 64  
More....................................................................................................................... 65  
Leased 128K.................................................................................................... 65  
Ldm 128 Master ............................................................................................. 65  
Factory Setup.................................................................................................. 66  
Chapter 9. Dial Options ................................................................................................... 67  
Dialing Options................................................................................................................... 67  
Hang Up Line............................................................................................................... 68  
Dial Number................................................................................................................. 68  
Redial Last Number .................................................................................................... 68  
Answer Call.................................................................................................................. 68  
Dial Stored Number .................................................................................................... 68  
Store/Review Number ............................................................................................... 69  
Chapter 10. Remote Configuration ................................................................................ 71  
Remote Configuration ....................................................................................................... 71  
Configuring with AT Commands ............................................................................. 71  
Configuring and Testing with the Front Panel or  
VT 100 Terminal ............................................................................................ 72  
Configure Remote Unit............................................................................................... 73  
Remote Testing............................................................................................................. 74  
Loopback Remote 1B ........................................................................................... 74  
Loopback Remote 2B ........................................................................................... 74  
Set Password......................................................................................................... 74  
Chapter 11. Troubleshooting........................................................................................... 77  
If Self Test Fails ................................................................................................................... 77  
If The ISU 128 Does Not READ READY......................................................................... 77  
Chapter 12. Specifications ............................................................................................... 83  
Specifications and Features............................................................................................... 83  
Network Interface.......................................................................................... 83  
DTE Interface ................................................................................................. 83  
Dialing Selections .......................................................................................... 83  
Data Rates (Network) ................................................................................... 83  
Data Rates (DTE) ........................................................................................... 83  
Rate Adaption ................................................................................................ 84  
Interoperability .............................................................................................. 84  
Switch Compatibility .................................................................................... 84  
B Channel Aggregation ................................................................................ 84  
Display ............................................................................................................ 84  
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Table of Contents  
Environmental ............................................................................................... 85  
Physical........................................................................................................... 85  
Power .............................................................................................................. 85  
Appendix A. AT Commands........................................................................................... 87  
Appendix B. Current Status Messages.......................................................................... 93  
Appendix C. Status Buffer Messages............................................................................ 97  
Appendix D. S-Register List ........................................................................................... 107  
Appendix E. Connector Pinouts ..................................................................................... 115  
Acronyms............................................................................................................................ 121  
Glossary .............................................................................................................................. 123  
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Table of Contents  
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ISU-128 User Manual  
61202.029L2-1  
 
List of Figures  
Figure 1-1:  
Figure 1-2:  
Figure 1-3:  
Figure 4-1:  
Figure 4-2:  
Figure 5-1:  
Figure 5-2:  
Figure 5-3:  
Figure 6-1:  
Figure 6-2:  
Figure 6-3:  
Figure 6-4:  
Figure 6-5:  
Figure 6-6:  
Figure 6-7:  
Figure 6-8:  
Figure 6-9:  
Figure 6-10:  
Figure 6-11:  
Figure 6-12:  
Figure 6-13:  
Figure 6-14:  
Figure 6-15:  
Figure 6-16:  
Figure 6-17:  
Figure 6-18:  
Figure 7-1:  
Figure 7-2:  
Figure 7-3:  
Figure 7-4:  
Figure 7-5:  
Figure 7-6:  
Figure 7-7:  
Figure 8-1:  
Figure 9-1:  
Figure 9-2:  
ISU 128 Rear Panel ................................................................................ 2  
ISU 128 Front Panel............................................................................... 3  
ISU 128 Interoperability........................................................................ 5  
VT 100 Status Screen ............................................................................. 17  
VT 100 Configuration Screen............................................................... 18  
VT 100 Test Screen................................................................................. 19  
Test Menu Tree ...................................................................................... 20  
Loopback Points .................................................................................... 20  
Dial Line Menu Tree ............................................................................. 23  
VT 100 Configuration Screen............................................................... 24  
Configuration Menu Tree..................................................................... 27  
Dial Options, RS-366 Menu Tree......................................................... 29  
Dial Options, V.25 bis Menu Tree....................................................... 33  
Dial Line, Auto Answer Menu Tree ................................................... 34  
Data Bits Menu Tree.............................................................................. 34  
V.25 bis ASYNC Menu Tree................................................................. 35  
Answer Tone Menu Tree...................................................................... 37  
Connect Timeout Menu Tree............................................................... 38  
Call Screening Menu Tree .................................................................... 38  
Leased Line Menu Tree ........................................................................ 40  
Limited Distance Modem Application............................................... 40  
Leased Application with Channel Banks........................................... 41  
Asynchronous DTE Options Menu Tree............................................ 42  
Synchronous DTE Options Menu Tree .............................................. 42  
Flow Control Menu Tree ...................................................................... 44  
Data Format Menu Tree ....................................................................... 45  
Protocol Menu Tree............................................................................... 48  
BONDING Mode 1 Protocol Menu Tree............................................ 49  
V.34 Error Control Menu Tree............................................................. 51  
V.34 Compression Menu Tree ............................................................. 52  
V.34 MNP Block Size Menu Tree ........................................................ 52  
FALLBACK Menu Tree ........................................................................ 55  
PPP Menu Tree ...................................................................................... 56  
Quick Setup Menu Tree........................................................................ 59  
VT 100 Terminal Dial Options Screen ................................................ 67  
Dial Menu Tree ...................................................................................... 68  
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ISU 128 User Manual  
vii  
 
List of Figures  
Figure 10-1:  
Figure 10-2:  
Figure 10-3:  
Figure 10-4:  
Figure 10-5:  
Figure 10-6:  
Figure E-1:  
Figure E-2:  
Figure E-3:  
Figure E-4:  
Figure E-5  
Remote Configuration Menu Path...................................................... 72  
Remote Configuration Screen.............................................................. 72  
Remote Unit Configuration Screen..................................................... 73  
Test Menu Path ...................................................................................... 74  
Loopback Remote 1B............................................................................. 75  
Set Password Screen.............................................................................. 75  
EIA-232/RS-530 Interface..................................................................... 115  
V.35 Interface.......................................................................................... 117  
RS-366 Interface...................................................................................... 118  
RJ-45 Interface ........................................................................................ 118  
Maintenance Port................................................................................... 119  
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ISU 128 User Manual  
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List of Tables  
Table 1-A:  
Table 1-B:  
Table 3-A:  
Table 7-A:  
Table E-A:  
Table E-B:  
Table E-C:  
Table E-D:  
Table E-E:  
Table E-F:  
DTE Indicators ....................................................................................... 3  
Recommended Operating Modes ....................................................... 7  
Maximum DTE Interface Cable Lengths............................................ 12  
Rate Adaption Protocols....................................................................... 54  
EIA-232 Interface ................................................................................... 115  
RS-530 Interface ..................................................................................... 116  
V.35 Interface.......................................................................................... 117  
RS-366 Interface ..................................................................................... 118  
RJ-45 ISDN IFC ...................................................................................... 118  
Maintenance Port................................................................................... 119  
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xi  
 
List of Tables  
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ISU 128 User Manual  
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Chapter 1  
Understanding ISDN and the ISU 128  
ISDN OVERVIEW  
The Integrated Services Digital Network (ISDN) is a public or private switched  
digital network. ISDN is an international standard for digital communica-  
tions, allowing a full range of enhanced services supporting voice, data, and  
image applications through standard interfaces over a single telephone wire.  
ISDN provides a means of integrating these services and modernizing com-  
munication networks for information movement and management efficiency.  
THE ADTRAN ISU 128  
The ADTRAN ISU™ 128 is a stand-alone device that connects data terminal  
equipment (DTE) to the ISDN network or to a leased digital network for data  
transmission. The ISU 128 allows high-speed data transmission (up to 128  
®
kbps) over a single ISDN line. The ISU 128 meets the Microsoft Windows 95  
Plug-an-Play specifications. The file MDMADTN.INF is required. To obtain  
this file contact our website at URL of www.adtran.com ADTRAN technical  
support. The number is located on the inside back cover of this manual.  
From the network, ISDN is delivered by a single 2-wire 2B1Q U-interface  
which is connected directly to the ISU 128. ISDN network termination is de-  
signed into the ISU 128, eliminating the need and expense of a separate NT1.  
For network testing, the ISU 128 responds to NT1 test commands from the tele-  
phone company central office (CO).  
The ISU 128 transmits data over an RS-530, V.35 interface, or EIA-232 interface,  
selectable on the front panel. The ISU 128 performs at synchronous data trans-  
fer rates of 2400 bps to 128 kbps and asynchronous rates of 300 bps to 115.2  
kbps. For speeds over 64 kbps, the industry standard BONDING or MULTI-  
LINK PPP protocol aggregates the two 64 kbps B channels for a maximum of  
128 kbps. The ISU 128 is intended to support the transfer of data and images  
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ISU 128 User Manual  
1
 
Chapter 1. Understanding ISDN and the ISU 128  
over ISDN. The ISU 128 may be viewed as an ISDN dial modem that allows  
cost-effective high-speed data transmission at rates up to 128 kbps.  
The ISU 128 has one RJ-45 jack available on the rear panel for network connec-  
tion (see Figure 1-1). The RJ-45 jack labelled ISDN IFC is for ISDN Basic Rate.  
ISDN Basic Rate service divides a standard telephone line into three digital  
channels capable of simultaneous voice and data transmission. The three  
channels are comprised of two bearer (B) channels at 64 kbps and one data (D)  
channel at 16 kbps (2B+D).  
The ISU 128 also supports a leased digital connection that allows data to be  
transferred at up to 128 kbps over a 2-wire facility using the U-interface jack  
labelled ISDN IFC. This type of service is a permanent connection between  
end points and is sometimes referred to as a leased connection, a dedicated  
connection, a nailed-up connection, a private circuit, or a limited distance mo-  
dem connection. These types of service are referred to in this manual as  
Leased Line Service.  
Figure 1-1  
ISU 128 Rear Panel  
Dialing from the ISU 128 is accomplished in a variety of ways:  
•
•
•
From the front panel  
From up to ten stored numbers  
Through an RS-366 dial port used in facsimile and video conferencing ap-  
plications  
•
•
Over the DTE interface using the AT command set  
With V.25 bis in-band dialing (used in applications such as LAN/WAN  
bridging)  
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ISU 128 User Manual  
61202.029L2-1  
 
Chapter 1. Understanding ISDN and the ISU 128  
•
With DTR asserted, some bridges/routers raise DTR when bandwidth on  
their dedicated line is exceeded. In high-traffic times, this allows the ISU  
128 to dial out over the ISDN for an extra 128 kbps of bandwidth-on-de-  
mand.  
The ISU 128 front panel accommodates a 2-line, 16 character LCD display.  
Seven LED indicators monitor data flow and display the status of key DTE in-  
terface leads as described in Table 1-A. A front panel keypad supports config-  
uration, test modes, test status, and dialing (see Figure 1-2).  
ISU 128  
1
4
2
5
3
6
ENTER  
7
8
0
9
RS CS TD RD CD TR SR  
CANCEL  
#
*
Figure 1-2  
ISU 128 Front Panel  
Table 1-A  
DTE Indicators  
Indicator  
Definition  
RS  
CS  
TD  
RD  
CD  
TR  
Request to Send. Indicates the DTE is ready to transmit.  
Clear to Send. Indicates the ISU 128 is ready to transmit.  
Transmit Data. On when the DTE is transmitting to the ISU 128.  
Receive Data. On when the ISU 128 is receiving data from the far end.  
Carrier Detect. On when the ISU 128 is connected to a remote unit.  
Data Terminal Ready from DTE. On when DTR is active at DTE interface.  
Data Set Ready.  
SR  
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Chapter 1. Understanding ISDN and the ISU 128  
ISU 128 INTEROPERABILITY  
Telephone networks are evolving from analog technologies to digital technol-  
ogies such as ISDN. This transition is time-consuming and costly for the tele-  
phone companies. Upgrading all locations and facilities is a lengthy process.  
The ISU 128 bridges this transition by supporting communications with exist-  
ing and future network services and equipment. The ISU 128 supports com-  
munications with Switched 56 service, Switched 56 DSUs (2-wire and 4-wire),  
various ISDN terminal adapters, ISDN terminal equipment, BONDING com-  
patible inverse multiplexers, and analog modems with the optional V.34 mo-  
dem (part number 1202029L3).  
Figure 1-3 illustrates the ISU 128 operation in various switched network ser-  
vices and customer premises products.  
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ISU 128 User Manual  
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Chapter 1. Understanding ISDN and the ISU 128  
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Chapter 1. Understanding ISDN and the ISU 128  
RECOMMENDED OPERATING PROTOCOLS  
The ISU 128 supports a wide range of operating modes. Many combinations  
of circuit type, protocol, and data rate may be selected. However, only the  
combinations shown in Table 1-B are recommended. As noted in Table 1-B, all  
asynchronous rates will support flow control. Flow control is required when  
operating at 115,200 bps using PPP (Point-to-Point Protocol), V.120, SAP (Sim-  
ple Adtran Protocol), or asynchronous bonding.  
Table 1-B shows that a given data rate may be achieved by more than one pro-  
tocol/rate adaption selection. The table is organized so that selections with  
the least transport delay are closer to the top of the table for any given circuit  
type. Therefore, users should choose a protocol and rate closer to the top of  
the protocol rate list for a given circuit type.  
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ISU 128 User Manual  
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Chapter 1. Understanding ISDN and the ISU 128  
Table 1-B  
Recommended Operating Modes  
Sync/  
Async  
Sync  
Sync  
Sync  
Sync  
Sync  
Sync  
Sync  
Call Type  
DIAL-64K  
Protocol  
Rates Supported (bps)  
BONDING  
Clear Chan  
PPP  
V.110  
V.120  
Tlink  
56000  
48000  
2400  
2400  
9600  
2400  
38400  
1200  
2400  
1200  
1200  
1200  
38400  
56000  
48000  
2400  
2400  
9600  
2400  
1200  
2400  
57600  
1200  
1200  
1200  
128000  
128000  
115200f  
115200f  
112000  
112000  
115200f  
115200f  
48000  
2400  
64000  
56000  
4800  
4800  
19200  
4800  
64000  
9600  
9600  
38400  
9600  
19200 38400 56000 64000  
19200 38400  
48000  
19200 56000 64000  
SAP  
PPP async-sync Async  
2400  
4800  
2400  
2400  
2400  
57600  
4800  
9600  
4800  
4800  
4800  
115200f  
9600  
19200 38400 57600  
115200f  
115200f  
BONDING  
V.110  
V.120  
Async  
Async  
Async  
Async  
Async  
Sync  
Sync  
Sync  
Sync  
Sync  
19200 38400 57600  
9600  
9600  
9600  
19200 38400v  
19200 38400 57600  
19200  
Tlink  
SAP  
DIAL-56K  
BONDING  
Clear Chan  
PPP  
V.110  
V.120  
56000  
4800  
4800  
19200  
4800  
2400  
4800  
9600  
9600  
38400  
9600  
4800  
9600  
19200 38400 56000  
19200  
48000  
Tlink  
Sync  
19200 56000  
PPP async-sync Async  
9600  
19200 38400 57600  
115200f  
115200f  
BONDING  
DSU 57.6  
V.110  
Async  
Async  
Async  
Async  
Async  
Sync  
19200 38400 57600  
2400  
2400  
2400  
4800  
4800  
4800  
9600  
9600  
9600  
19200  
19200 38400 57600  
19200  
V.120  
Tlink  
DIAL-64K*2 BONDING  
MPPP  
MPPP  
BONDING  
Sync  
Async  
Async  
Sync  
DIAL-56K*2 BONDING  
MPPP  
MPPP  
BONDING  
Sync  
Async  
Async  
Sync  
LEASED 64K Clear Chan  
56000  
4800  
64000  
9600  
SAP  
Sync  
19200 38400  
9600 19200 38400 57600f  
DSU 57.6  
Async  
Async  
Sync  
57600  
1200  
128000  
57600f  
SAP  
LEASED 128K Clear Chan  
SAP  
2400  
4800  
115200f  
Async  
115200f  
1. All asynchronous rates support flow control.  
2. All dial-up modes support front panel, DTR, RS-366, AT command, and V.25 bis dialing  
methods.  
3. Rates marked with f require flow control.  
4. Given a choice between two protocols, pick the protocol closer to the top of the list.  
5. Multilink PPP supports the same rates as single-link PPP async-sync. Use the recom-  
mended rates for PPP async-sync.  
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Chapter 1. Understanding ISDN and the ISU 128  
8
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Chapter 2  
ISDN Ordering Codes (IOCs)  
ORDERING ISDN USING IOCS  
The development of ISDN ordering codes (IOCs) simplifies the process of or-  
dering ISDN service. The ISDN Solutions Group, a consortium of ISDN equip-  
ment vendors, service providers, and Bellcore, established these codes to  
represent predetermined line configurations for ISDN Basic Rate service for  
specific applications.  
ADTRAN and Bellcore have registered and tested eight generic IOCs. Of  
these, four are recommended for operation of the ISU 128. After reviewing  
the following list, order ISDN lines from the local service provider. Request  
the appropriate IOC for your application. They are described in detail in this  
chapter.  
In some areas, ISDN tariffs may warrant the use of ordering codes with less  
features. For example, in a particular region, there may be additional monthly  
expense associated with having voice service on each B channel. If you have a  
data only application, Capability R (previously Generic Data I) may be more  
cost-effective.  
If these are not available from your service provider or you would like more  
information regarding ordering ISDN see the ADTRAN document Ordering  
ISDN Service User Guide part number 60000.015-8 or contact your telephone  
company for alternative line configurations. The Ordering ISDN Service User  
Guide is available on the ADTRAN home page at http://www.adtran.com or  
by calling ADTRAN.  
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Chapter 2. ISDN Ordering Codes (IOCs)  
ADTRAN has registered the following ISDN ordering codes to support a va-  
riety of tariffs and applications:  
Capability S  
•
•
•
2B service  
Both B channels alternating voice and data  
Two directory numbers  
Applications  
•
Host data center, internet access, bulletin board, and modem pooling ap-  
plications  
•
•
Modem capability  
Generic data transfer, including remote access and LAN/WAN connectiv-  
ity and telecommuting  
Capability R  
•
•
•
2B service  
Data only  
Two directory numbers  
Applications  
•
Host data center, internet access, bulletin board, and modem pooling ap-  
plications  
•
•
Data only applications, no modem capability  
Data transfer applications, including remote access and LAN/WAN con-  
nectivity, telecommuting  
Capability B  
•
•
•
•
1B service  
Data only  
One directory number  
Capability C  
•
•
•
1B service  
Alternating voice and data  
One directory number  
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Chapter 3  
Installation  
After unpacking the unit, immediately inspect it for possible shipping dam-  
age. If damage is discovered, file a claim immediately with the shipping car-  
rier, then contact ADTRAN Repair and Return Department (see the end of this  
manual).  
Ensure that a grounded, 115 VAC, 60 Hz receptacle is used to provide power.  
NETWORK CONNECTION  
The ISU 128 supports either dial or leased operation. An eight-pin RJ-45 mod-  
ular jack labelled ISDN IFC on the rear panel allows connection to ISDN Basic  
Rate Service provided by the telephone company or to a leased type of service.  
Dial operation uses the ISDN Basic Rate U-interface and allows the ISU 128 to  
dial out over the ISDN network. The Leased Line Service can be dedicated  
2B1Q data service or a nailed-up circuit (twisted pair) that provides a dedicat-  
ed connection between end points such as a limited distance modem or point-  
to-point connection. When using the ISU 128 in either of these types of service,  
connect the network interface to the RJ-45 connector labelled ISDN IFC.  
See the appendix Connector Pinouts for network connection pin assignments.  
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Chapter 3. Installation  
DTE DATA CONNECTION  
Data terminal equipment is connected to the ISU 128 by using either the RS-  
530 interface, the V.35 interface, or EIA-232 interface on the rear panel of the  
ISU 128. The maximum recommended cable lengths are shown in Table 3-A.  
See the appendix Connector Pinouts for each interface pin assignments. Be sure  
to configure the menu option for the connector type used in your application.  
Refer to the section DTE Options for Asynchronous and Synchronous Operation in  
Chapter 6 to configure the connector type.  
Table 3-A  
Maximum DTE Interface Cable Lengths  
DTE Interface  
Max Cable Length  
RS-530  
V.35  
50 feet  
30 feet  
15 feet  
EIA-232  
The RS-530 interface and the V.35 interface support data rates up to 128 kbps.  
The DTE rate is configured from the front panel of the ISU 128 or by using AT  
commands. See the chapter Configuration to configure the ISU 128 with the ap-  
propriate data rates.  
To prevent possible radio frequency interference emissions, a shielded V.35  
cable is required.  
DIAL INTERFACE CONNECTION  
If out-of-band RS-366 dialing is required for applications such as videoconfer-  
encing or FAX machines, the dialing interface of the host DTE should be con-  
nected to the dial port marked RS-366/Maintenance. Pin assignments for the  
RS-366 connector are listed in the appendix Connector Pinouts.  
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Chapter 3. Installation  
MAINTENANCE INTERFACE  
The Maintenance Interface is available at 9600 bps, 8 data bits, no parity, asyn-  
chronous format, through the RS-366/Maintenance port. See the appendix  
Connector Pinouts for Maintenance port pin assignments. The VT 100 terminal  
or null modem can be connected to the RS-366/Maintenance port using an  
EIA-232 cable. This interface can be used to set internal S-registers, dial ISDN  
connections, and disconnect calls. This port also allows ADTRAN Technical  
Support personnel to retrieve vital information from the unit if a problem is  
encountered during initial configuration of the ISU 128. Most problems can be  
solved without resorting to this port for assistance.  
In order to activate the Maintenance port, ensure the dial mode is either Front  
Panel or AT commands. When the dial mode is set for RS-366, the Mainte-  
nance port is disabled.  
The Maintenance port cannot be used to pass data or to remotely configure another  
ISU 128 using the Cfg. Rmt. Unit option.  
AT commands sent to the Maintenance port are not preceeded by "AT."  
Example: To display the unit model number, enter: I0  
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Chapter 3. Installation  
14  
ISU 128 User Manual  
61202.029L2-1  
 
Chapter 4  
Operation  
MENU NAVIGATION  
Four function keys on the left-hand side of the keypad allow the user to enter,  
exit, and scroll through the various menu branches. The four function keys are  
defined below.  
Enter  
Enters the selected item.  
Scrolls up a menu tree.  
Scrolls down a menu tree.  
Up Arrow  
Down Arrow  
Cancel  
Exits (back one level) from the current branch of  
the menu tree.  
For reading ease, function keys are represented in bold, initial caps text. Selectable  
menu items and messages displayed on the LCD are represented in bold type as they  
appear on the LCD.  
Press either the Up or Down arrow to scroll through the menu tree. To choose  
an item, press the corresponding number on the keypad. The item blinks to  
show that it is selected and has been stored in non-volatile memory. Press En-  
ter to select the item. Press Cancel to exit back through the menu tree.  
It is important to note that some features in the ISU 128 do not immediately  
take effect upon selection. This prevents unintentional reconfiguration of the  
ISU 128 during an active call. Leased/Dial Line, and ISDN Switch Protocl,  
take effect only when the ISU is powered up or the U-interface is bounced (line  
broken and restored). To ensure the ISU is actually performing as configured,  
cycle the power off, then back on again, after these items are changed. Also,  
items such as Bit Rate, Protocol, and Call Type take effect only at the begin-  
ning of a new call.  
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Chapter 4. Operation  
GETTING STARTED  
At power up, the front panel display is in the Current Status mode. This is the  
recommended resting place for the display as it shows the current operational  
status of the unit. For example, if the ISU 128 is not connected to the network,  
the Current Status menu displays ADTRAN ISU 128 Link Down. If the unit  
is connected to the network and functioning properly, it displays ADTRAN  
ISU 128 Ready. A list of Current Status messages is provided in the appendix  
Current Status Messages. Pressing Cancel repeatedly returns the unit to the  
Current Status menu. While at the Current Status menu, pressing any key  
changes the display to the top of the menu tree.  
The menu tree allows for set up and operation of the ISU 128 from the front  
panel. The main branches of the menu tree follow:  
1. STATUS  
2. TEST  
3. CONFIG (Configuration)  
4. DIAL  
Status Buffer  
Select 1=STATUS from the top of the menu tree to display the status buffer.  
The Up and Down arrows allow viewing of the last fifty status messages gen-  
erated during the operation of the unit. The most recent message displays last.  
An explanation of Status Buffer Messages can be found in the appendix Status  
Buffer Messages. To return to the top of the menu, press Cancel. The buffer can  
be cleared by pressing 0.  
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Chapter 4. Operation  
VT 100 TERMINAL MENU SUPPORT  
When connected to an asynchronous VT 100 terminal or VT 100 terminal em-  
ulator, use the built-in ISU 128 menu system for configuration. To enter into  
the menus, type AT!V Enter. To go to a particular menu, simply press the hot  
keys for that menu. The main branches of the menu tree and their hot keys are:  
•
•
•
•
STATUS (Ctl-V)  
TEST (Ctl-T)  
CONFIG (Ctl-C)  
DIAL (Ctl-D)  
Status Screen  
To determine the current status of the unit, press Ctrl+V to access the Status  
Screen (see Figure 4-1). The Status Screen displays unit information such as  
the loop status, software revision, the result of the initial self test, and the sta-  
tus buffer messages. The most recent message always displays as Status Buff-  
er 1. An explanation of status buffer messages can be found in the appendix  
Status Buffer Messages.  
Figure 4-1  
VT 100 Status Screen  
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Chapter 4. Operation  
Configuration Screen  
Once the unit is selected using the terminal interface, the display shows the  
Configuration Menu (see Figure 4-2). This screen shows the current configura-  
tion, line, and call status for the selected unit. See the chapter Configuration for-  
more information about configuring the ISU 128.  
Figure 4-2  
VT 100 Configuration Screen  
To configure the ISU 128 quickly and easily for most applications, see the  
chapter Quick Setup.  
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ISU 128 User Manual  
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Chapter 5  
Testing  
TEST OPTIONS  
Pressing Ctl-T from any VT 100 terminal screen or selecting 2=TEST from the  
top of the menu tree on the front panel displays local testing options. Figure  
5-1 shows the VT 100 terminal test screen and the menu tree is illustrated in  
Figure 5-2.  
Figure 5-1  
VT 100 Test Screen  
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ISU 128 User Manual  
19  
 
Chapter 5. Testing  
1=Loopback DTE  
2=Loopback Netw.  
3=Loopback Proto  
4=Loopback Remote  
5=Test Remote  
6=Lpbk Disable  
7=NEBE/FEBE  
1=STATUS  
2=TEST  
3=CONFIG  
4=DIAL  
1=No Rem Lpbks  
2=DDS Accepted  
3=V54 Accepted  
4=DDS + V54 Accept  
0=Software Ver  
Figure 5-2  
Test Menu Tree  
Loopback DTE  
Loopback DTE causes the ISU DTE port to loop back toward user equipment.  
This allows performance of a bit error rate test (BERT) between the ISU 128  
and the end user equipment to verify proper cable connection.  
Loopback Network  
Loopback Network forces the ISU 128 to loopback both the B1 and B2 chan-  
nels toward the network. This can be used to allow a far-end user to perform  
a BERT all the way through the network.  
Loopback Protocol  
Loopback Protocol allows data to loopback toward the network after passing  
through a selected protocol such as T-Link or BONDING. See Figure 5-3 for  
loopback points.  
RATE  
ADAPTION  
NET  
IFC  
DTE  
Protocol  
DTE  
IFC  
Network  
NETWORK  
DTE  
Figure 5-3  
Loopback Points  
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ISU 128 User Manual  
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Chapter 5. Testing  
Loopback Remote  
Loopback Remote allows the ISU 128 to issue a V.54 in-band loopback com-  
mand to a far-end unit while still accepting data from the DTE connector. This  
provides bit error rate testing of an entire link using an external BERT test set.  
To use this feature, both units must be configured for Clear Channel operation  
and the far-end unit must be able to respond to V.54 loopback commands. See  
the chapter Protocol Options to configure the unit for Clear Channel operation.  
Press the Cancel key to end the test.  
Loopback Remote 1B and 2B are only used with the DTE set to asynchronous.  
Test Remote  
Test Remote allows the ISU 128 to issue a V.54 in-band loopback command to  
a far-end unit and BERT the link using a built-in 2047 pattern generator/  
checker. This allows for testing a circuit without any extra test equipment. To  
use this feature, both units must be configured for Clear Channel operation  
and the far-end unit must be able to respond to V.54 loopback commands. See  
the chapter Protocol Options to configure the unit for Clear Channel operation.  
The built-in 2047 pattern generator/checker displays the number of bytes  
transmitted on the top line and the number of errored bytes received on the  
lower line of the front panel display. Press 0 to clear the counts. By pressing  
the down arrow, you can loop down the far end unit and run a head to head  
2047 pattern test. Press Cancel to end the test.  
Loopback Disable  
The following options are available when disabling loopbacks:  
No Remote Loopbacks  
The ISU 128 ignores all V.54 and DDS loopback commands.  
DDS Accepted  
The ISU 128 responds to DSU Latching Loopback commands. This option  
only takes effect if the unit is in leased line mode.  
V.54 Accepted  
The ISU 128 responds to V.54 loopback commands.  
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Chapter 5. Testing  
DDS+V54 Accept  
The ISU 128 responds to both DSU Latching Loopback commands (leased line  
mode only) and V.54 loopback commands.  
The ISU must be optioned for Clear Channel operation for DSU Latching and V.54  
loopback commands to take effect.  
Near-End Block Errors/Far-End Block Errors (NEBE/FEBE)  
NEBE/FEBE allows the user to determine the quality of the network connec-  
tion by viewing the number of near-end (NEBE) and far-end (FEBE) block er-  
rors occurring on the ISDN interface. A large or incrementing count indicates  
problems with network equipment. An incrementing or large count of NEBEs  
indicates problems from the switch to the terminal adapter. An incrementing  
or large count of FEBEs indicates problems in the direction from the terminal  
adapter to the switch.  
Software Version  
Software Ver displays the software version and checksum in use on the ISU  
128.  
Press Cancel to exit any of these options.  
22  
ISU 128 User Manual  
61202.029L2-1  
 
Chapter 6  
Configuration  
DIAL LINE OPERATION  
This section explains how to configure the ISU 128 when using ISDN basic rate  
switched service. Figure 6-3 illustrates the entire CONFIG branch of the menu  
tree.  
The following are step-by-step procedures for configuring the unit for dial line  
operation, switch protocol, call type, terminal ID, dial options, auto answer,  
answer tone, connect timeout, and call screening.  
To dial calls over the ISDN, the unit must be configured for Dial Line. The  
menu path to select Dial line operation is shown in Figure 6-1.  
1=Dial Line  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
3=CONFIG  
4=Quick setup  
5=Remote config  
Figure 6-1  
Dial Line Menu Tree  
When using a VT 100 terminal, press Ctl-C to access the Configuration screen,  
then set the Line type option to Dial Line. The Configuration screen appears  
as shown in Figure 6-2.  
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ISU 128 User Manual  
23  
 
Chapter 6. Configuration  
Figure 6-2  
VT 100 Configuration Screen  
Switch Protocol  
Find out what kind of ISDN switch your local CO is using by asking the tele-  
phone administrator or telephone company representative. Configure the ISU  
®
®
128 for either a Northern Telecom DMS-100 , AT&T 5ESS switch, or a switch  
conforming to the National ISDN-1 standard (usually an AT&T 5ESS, NTI  
DMS-100, or Siemens EWSD). In the Far East, configure for the NEC switch.  
Call Type  
The call type can be configured four different ways, depending on the type of  
service used: speech, audio, data 56 kbps, or data 64 kbps.  
When placing outgoing calls using the optional V.34 modem, the unit must be op-  
tioned for either speech or audio call type.  
Speech  
Speech directs the call control software to request a Mu-law/A-law speech cir-  
cuit as the bearer capability for outgoing calls. The Speech option is used with  
an ISDN line configured for voice service. In some areas voice service costs  
24  
ISU 128 User Manual  
61202.029L2-1  
 
Chapter 6. Configuration  
less than data service. A Speech call type does not guarantee an end-to-end  
digital connection with some local and long distance carriers.  
Audio  
Audio directs the call control software to request a 3.1 kHz audio circuit as the  
bearer capability for outgoing calls. The Audio option is used with an ISDN  
line configured for voice service. In some areas audio service is less expensive  
than data service. Selecting an Audio call type guarantees a digital end-to-end  
ISDN connection.  
Data 56 kbps  
Data 56 kbps directs the call control software to request a 64 kbps data circuit  
that is rate-adapted to 56 kbps. Data 56 kbps is intended for use in circum-  
stances where interoperability with Switched 56 service is desired.  
Data 64 kbps (default)  
The default Call type for ISDN service is Data 64 kbps. This directs the call  
control software to request an unrestricted 64 kbps circuit.  
Terminal Identification  
Terminal identification is assigned by the local telephone company and con-  
sists of a Service Profile Identifier (SPID) and Local Directory Number (LDN).  
Setting the SPID  
The SPID is a sequence of digits used to identify ISDN terminal equipment to  
the ISDN switch. The SPID is assigned by the local phone company when the  
ISDN line is installed and it usually looks similar to the phone number. Obtain  
SPIDs from the telephone administrator or local telephone representative.  
The number of SPIDs required (0, 1, or 2) depends on how your ISDN line is  
configured. For instance, a point-to-point line has no SPID. Multipoint lines  
may have one or two SPIDs. The ISU 128 uses the presence of SPID 1 to deter-  
mine if the line is multipoint. If the line has only one SPID, then it must be en-  
tered in SPID 1.  
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25  
 
Chapter 6. Configuration  
When selecting a SPID, use the Up and Down arrows to choose between  
SPID 1 and SPID 2. Press Enter to select the SPID and use the keypad to enter  
the SPID number. While entering/editing a SPID, the Down arrow allows ou  
to backspace through the number string to correct mistakes. The Up arrow  
scrolls back to the last digit entered. To cancel a number, use the Down arrow  
to backspace through it and press Enter. Press Enter after entering each SPID.  
To abort changes at any time, press Cancel.  
Disconnect the network interface from the unit before initially entering and/or altering  
the SPIDs or LDNs.  
Setting the LDN  
This option allows the entry of 0, 1, or 2 LDNs. The LDN is used when placing  
or receiving BONDING calls. The LDN is the seven-digit local phone number  
assigned to the line.  
When entering and LDN, use the Up and Down arrows to choose between  
LDN 1 and LDN 2. Press Enter to select the LDN and use the keypad to enter  
the LDN number. While entering/editing an LDN, the Down arrow allows  
you to backspace through the number string to correct mistakes. The Up arrow  
scrolls back to the last digit entered. To cancel a number, use the Down arrow  
to backspace through it and press Enter. Press Enter after entering each LDN.  
To abort changes at any time, press Cancel.  
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ISU 128 User Manual  
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Chapter 6: Configuration  
1=Switch protocl  
2=Call type  
1=AT&T 5ESS  
2= DMS-100  
3=National ISDN1  
4=NEC Switch  
S
‘Buffer Display’  
1=Speech  
2=Audio  
3=Data 56Kbps  
4=Data 64Kbps  
1=Loopback DTE  
2=Loopback Netw.  
3=Loopback Proto  
4=Loopback Remote  
5=Test Remote  
6=Lpbk Disable  
7=NEBE/FEBE  
8=Software Ver  
3=Terminal ID  
4=Dial options  
Set SPID  
Set LDN  
1=No Rem Lpbks  
2=DDS Accepted  
3=V54 Accepted  
4=DDS + V54 Accept  
1=Front Panel  
2=RS-366  
3=AT commands  
4=V.25  
1=1 sec or EON  
2=2 sec or EON  
3=5 sec (default)  
4=10 sec or EON  
5=20 sec or EON  
1=V.25 HDLC  
2=V.25 ASYNC  
3=V.25 BISYNC  
5=Disabled  
5=Auto answer  
6=Answer tone  
1=Disabled  
2=Enabled  
3=Dump all calls  
4=V.25 HDLC FLAG 6=Wait for EON  
1=Netw. options  
1=Dial Line  
6=19200  
7=38400  
8=57600  
9=115200  
1=Bit Rate  
1=300  
2=1200  
3=2400  
4=4800  
5=9600  
1=No answer tone  
2=Incoming tone  
3=Outgoing tone  
4=Always tone  
1=RS-530  
2=V.35  
3=RS-232  
2=Connector Type  
7=Connect Timout 1=15 sec  
2=30 sec (def)  
3=1 minute  
4=2 minute  
5=4 minute  
1=1 Ms delay  
2=18 Ms delay  
3=RTS Options  
4=CTS Options  
5=CD Options  
1=Forced CTS  
2=Follows RTS  
8=Call Screening 1=Answer any  
2=ansr if SNO…9  
1= CD Forced on  
2=Normal  
3=Off with LOCD  
4=Off with Link Down  
2=Leased Line  
1=Clock mode  
2=Channel rate  
1=Slave  
2=Master  
1=64k  
2=128k  
1=Ignore DTR  
6=DTR Options  
2=Cmd when Off  
3=Idle when Off  
4=Off>On dial #0  
5=Dial #0 if On  
6=Answer if On  
7=Dial/Ans if On  
1=Asynchronous  
2=Synchronous  
2=DTE options  
3=Protocol  
1=Bit Rate  
1=2400  
2=4800  
3=9600  
6=48000  
7=56000  
8=64000  
G
1=TXINIT  
2=TXFA  
1=Clear Channel  
2=BONDING mode 1  
3=V.120  
3=TXADD01  
4=TXDEQ  
5=TANULL  
6=TCID  
4=19200 9=112000  
5=38400 0=128000  
1=DSR forced on  
2=OFF Idle+Test  
3=OFF Link Down  
7=DSR Options  
4=V.34  
5=V.110  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
2=Connector Type 1=RS-530  
2=V.35  
3=RS-232  
1=Error Ctrl  
2=Compression  
3=MNP Blk Size  
1=Normal  
2=Direct  
3=Reliable MNP  
4=Auto-Rel MNP  
5=Force LAPM  
6=Force MNP  
1=Hardware Flow  
2=Software Flow  
3=No Flow Ctrl  
8=Flow Control  
9=Data Format  
.
3=RTS Options  
4=CTS Options  
5=CD Options  
1=1 Ms delay  
2=18 Ms delay  
9=FALLBACK  
0=PPP asyn-sync  
1=Fallback Def  
1=Clear Channel  
2=BONDING mode 1  
3=V.120  
4=V.34  
5=V.110  
1=Method  
2=TBD  
1=Data Bits  
1=8 Data Bits  
1=Forced CTS  
2=Follows RTS  
1=PPP  
2=Multilink PPP  
3=PPP w/Comp  
4=Quick setup  
1=Dial 56K sync  
2=Dial 64Ksync  
3=Dial 112K sync  
4=Dial 128K sync  
5=Dial PPP  
6=V.34 1152 async  
7=Dial 57.6 asyn  
8=Dial 115.2 asy  
9=Fallback 57.6k  
0=More  
2=7 Data Bits  
2=Parity Bits  
1=None  
2=Odd  
3=Even  
1=CD Forced on  
2=Normal  
3=Off with LOCD  
4=Off with Link Down  
1=No Compression  
2=Compress MNP5  
3=Compress V42  
4=Comp V42/MNP5  
6=DSU 57.6 ASYNC  
7=T-LINK  
3=Stop Bits  
1=1 Stop bit  
8=SAP  
2=1.5 Stop bits  
3=2 Stop Bits  
1=Leased 128k  
2=Ldm 128 Master  
3=TBD  
4=TBD  
5=TBD  
6=DTR Options  
1=Ignore DTR  
9=PPP asyn-sync  
2=Cmd when Off  
3=Idle when Off  
4=Off>On dial #0  
5=Dial #0 if On  
6=Answer if On  
7=Dial/Ans if On  
1=64 bytes  
2=128 bytes  
3=192 bytes  
4=256 bytes  
6=TBD  
7=TBD  
5=Remote config  
1=Cfg. Rmt. Unit  
2=Set Password  
3=Loopback remote 1B  
4=Loopback remote 2B  
7=DSR Options  
1=DSR forced on  
2=OFF Idle+Test  
3=OFF Link Down  
1=Hang up line  
2=Dial number  
3=Redial last #  
4=Answer Call  
5=Dial Stored #  
6=Store/Review #  
8=Transmit Clock  
1=Normal  
2=External  
Configur  
1
ISU 128 User Manual  
27  
 
Chapter 6: Configuration  
28  
ISU 128 User Manual  
 
Chapter 6. Configuration  
Dial options  
The ISU 128 can be configured to dial using the Front Panel, RS-366 port, AT  
Commands, or V.25 bis Commands. Figure 6-4 illustrates the menu tree.  
Front Panel  
To establish and disconnect calls from the front panel keypad, configure Dial  
options for Front Panel. See the section Front Panel Dialing Options for more  
detail.  
RS-366  
To establish and disconnect calls using the RS-366 parallel dialing port, config-  
ure the unit for RS-366 dialing. This enables the RS-366 port on the rear of the  
unit. Whenever this dialing mode is enabled, DTR must be active before a call  
is placed. The call may be disconnected by dropping DTR, or from the front  
panel by selecting the #(pound) key to go directly to the Dial menu and select-  
ing 1=Hang up line, then Enter.  
DTE RS-366 dialers can end a string of dialed numbers in two different ways.  
The end of number (EON) alerts the ISU 128 that the entire number has been  
sent. Another method is to simply stop sending numbers and allow the ISU to  
time out, then dial the number. The ISU 128 supports both methods of dialed  
number terminations. The following options in Figure 6-4 allow for fine-tun-  
ing the dialed number termination.  
1=Switch protocl  
2=Call type  
1=Front Panel  
1=Dial Line  
3=Terminal ID  
1=1 sec or EON  
1=2 sec or EON  
3=5 sec or (default)  
4=10 sec or EON  
5=20 sec or EON  
6=Wait for EON  
2=RS-366  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=AT commands  
4=V.25  
3=CONFIG  
5=Disabled  
4=Quick setup  
5=Remote config  
Figure 6-4  
Dial Options, RS-366 Menu Tree  
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Chapter 6. Configuration  
1 sec or EON  
The ISU 128 assumes the dial string is fully entered if more than one second  
elapses since the last digit was entered, or the unit receives the EON com-  
mand.  
2 sec or EON  
The ISU 128 assumes the dial string is fully entered if more than two seconds  
elapse since the last digit was entered, or the unit receives the EON command.  
5 sec or EON (default)  
The ISU 128 assumes the dial string is fully entered if more than five seconds  
elapse since the last digit was entered, or the unit receives the EON command.  
This is the factory default setting.  
10 sec or EON  
The ISU 128 assumes the dial string is fully entered if more than 10 seconds  
elapse since the last digit was entered, or the unit receives the EON command.  
20 sec or EON  
The ISU 128 assumes the dial string is fully entered if more than 20 seconds  
elapse since the last digit was entered, or the unit receives the EON command.  
Wait for EON  
The ISU 128 assumes the dial string is fully entered only if the unit receives the  
EON command.  
AT Commands  
Configuring the ISU 128 for AT commands enables in-band dialing over the  
DTE interface using asynchronous AT commands. AT commands can be used  
to set up the ISU 128 as well as establish and end a call. Calls can be discon-  
nected from the front panel (as previously described) or from the far-end unit.  
When AT commands are selected, the DTE port becomes dual purpose. First,  
while a call is not established, the port accepts AT commands. During this  
time, the Carrier Detect (CD) signal is inactive. Second, when a call is estab-  
lished, the port is used for data. This data mode is indicated by the CD signal  
active. See the appendix AT Commands for a listing of the supported AT com-  
mands and their functions. In addition to the front panel, the ISU 128 can be  
configured and controlled with in-band AT commands from an asynchronous  
DTE port.  
30  
ISU 128 User Manual  
61202.029L2-1  
 
Chapter 6. Configuration  
To exit the data mode and enter the command mode, the asynchronous DTE  
device must transmit a proper escape sequence to the ISU 128. A specified  
time delay must occur between the last data character and the first escape se-  
quence character. This is the guard time delay, and it can be changed by writ-  
ing a value to the S12 register. The default value for the guard time is one  
second. For a valid escape sequence to occur, the DTE must transmit the es-  
cape code character three times in succession with delay between each charac-  
ter being less than the guard time. The default escape sequence is +++.  
Once the command mode is entered, AT commands can be transmitted to the  
ISU 128 to configure most of the options, dial remote DSUs, or initiate tests to  
check both the ISU 128 and the network connections. All command lines must  
begin with the AT character set in either capital or lower case letters and end  
with a terminating character. A command line can be terminated at any time  
by transmitting the Ctl-X (ASCII 018) after the AT attention code. The ISU 128  
ignores this command line and issues an OK response.  
The command line may contain a single command or a series of commands af-  
ter the AT attention code. When a series of commands are used, the individual  
commands may be separated with spaces for readability. The maximum  
length for a command line is 40 characters. Each command line is executed by  
the ISU 128 upon receipt of a terminating character.  
The default terminating character is a carriage return (ASCII 013), but it can be  
changed by writing a different value to register S3. Before the terminating  
character is transmitted, the command line can be edited by using the back-  
space character (ASCII 008) to erase errors so the proper commands can be en-  
tered. Examples of using AT commands are provided in this section.  
Using AT Commands  
Type AT followed by the letter of the command and numeric value of the set-  
ting desired and then press Enter. The following command returns the soft-  
ware version of the unit:  
ATI1  
Using S-Registers  
The configuration of the ISU 128 can be changed and/or reviewed with S-reg-  
isters. See the appendix S-Register List for a description of each S-register and  
its corresponding range of values.  
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Chapter 6. Configuration  
Reading S-Registers  
Type ATS followed by the number of the S-register to be read followed by a  
question mark and press Enter.  
ATS0?  
Reading S-Register Strings  
The ISU 128 uses S-register strings to store strings of digits for stored phone  
numbers, SPIDs, etc. Type ATSS followed by the number of the string S-reg-  
ister to be read followed by a question mark and press Enter.  
ATSS80?  
Changing S-Registers  
Type ATS followed by the number of the S-register to be changed, an equal  
sign, the numeric value to be assigned to the register, then press Enter.  
ATS0=2  
Changing S-Register Strings  
Type ATSS followed by the number of the string S-register to be changed, an  
equal sign, the numeric string to be assigned to the register, then press Enter.  
ATSS80=5551212  
Dialing a Call Using the AT Command Processor  
To dial a number using the DTE terminal and AT commands type ATD and  
the telephone number on one line and press Enter.  
ATD5551212  
When the dialing process begins, the front panel reads Dialing 5551212. If the  
call is successful, Connect is displayed on the front panel, followed by the rate  
adaption protocol in use and the bit rate. If the call is not successful, the front  
panel displays Disconnect followed by Ready. At this point the unit is ready  
for another call. The status buffer can be examined to find the reason for an  
unsuccessful call.  
To end an active call with the AT command processor, press the break in key  
sequence (+++) or the redefined key, then type ATH and press Enter to hang  
up the line.  
32  
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Chapter 6. Configuration  
V.25 bis  
Configuring the ISU 128 for V.25 bis (see Figure 6-5) enables in-band dialing  
over a DTE interface using asynchronous or synchronous V.25 bis commands.  
V.25 bis can be used to establish and end a call. Disconnecting calls can also  
be done from the front panel (as previously described) or from the far-end  
unit.  
V.25 bis dialing is used primarily by DTE with synchronous interfaces  
(HDLC/SDLC or BSC/BISYNC) not supporting the AT command set, which  
is commonly used by asynchronous devices. The ISU 128 supports V.25 bis in-  
band dialing in accordance with Fascicle VIII.I - V.25 bis (Malaga-Torremoli-  
nos 1984, Melbourne 1988).  
1=Switch protocl  
2=Call type  
1=Front Panel  
1=Dial Line  
3=Terminal ID  
2=RS-366  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=AT commands  
4=V.25  
3=CONFIG  
1=V.25 HDLC  
5=Disabled  
2=V.25 ASYNC  
3=V.25 BISYNC  
4=V.25 HDLC FLAG  
4=Quick setup  
5=Remote config  
Figure 6-5  
Dial Options, V.25 bis Menu Tree  
Recommendation V.25 uses the following DCE/DTE control signals:  
Transmitted data .......................................................... circuit 103  
Received data................................................................ circuit 104  
Ready for sending ........................................................ circuit 106  
Data set ready ............................................................... circuit 107  
Data terminal ready .................................................circuit 108/2  
Calling indicator........................................................... circuit 125  
The ISU 128 supports the following V.25 bis commands to control automatic  
calling and answering:  
CRN..................................... call request (number in command)  
CRS.......................................call request (using stored number)  
PRN ........................................................program stored number  
RLN ..................................................................list stored number  
CIC..............................................................connect incoming call  
DIC ........................................................disconnect incoming call  
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Chapter 6. Configuration  
When using stored numbers, V.25 bis accesses stored numbers 1 through 9 used by  
front panel dialing. See Front Panel Dialing Options.  
Auto Answer should be set to Disabled (shown in Figure 6-6) if V.25 bis is in  
control of answering incoming calls with the CIC/DIC commands, since the  
other settings for Auto Answer will override V.25 control of the answer func-  
tion.  
1=Switch protocl  
2=Call type  
1=Dial Line  
3=Terminal ID  
1=Disabled  
2=Enabled  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=CONFIG  
3=Dump all calls  
4=Quick setup  
5=Remote config  
Figure 6-6  
Dial Line, Auto Answer Menu Tree  
V.25 ASYNC Dialing  
V.25 bis specifies that the characters should be ASCII, 7 bits, even parity and  
one stop bit. However, for versatility the ISU 128 allows the data, parity, and  
stop bits as defined under Data bits. (See Figure 6-7.)  
1=Bit Rate  
2=Connector Type  
3=RTS Options  
1=Netw. options  
4=CTS Options  
1=Asynchronous  
2=DTE options  
3=CONFIG  
5=CD Options  
6=DTR Options  
7=DSR Options  
8=Flow Control  
9=Data Format  
2=Synchronous  
3=Protocol  
4=Quick setup  
5=Remote config  
1=8 Data bits  
2=7 Data bits  
1=Data Bits  
2=Parity Bits  
3=Stop Bits  
Figure 6-7  
Data Bits Menu Tree  
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Chapter 6. Configuration  
The setting in Figure 6-8 allows for V.25 bis messages in asynchronous (start/  
stop) data format.  
1=Switch protocl  
2=Call type  
1=Front Panel  
1=Dial Line  
3=Terminal ID  
2=RS-366  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=AT commands  
4=V.25  
3=CONFIG  
1=V.25 HDLC  
5=Disabled  
2=V.25 ASYNC  
3=V.25 BISYNC  
4=V.25 HDLC FLAG  
4=Quick setup  
5=Remote config  
Figure 6-8  
V.25 bis ASYNC Menu Tree  
Although V.25 bis allows asynchronous data format, asynchronous DTE is  
more likely to support the AT command set than V.25 bis.  
V.25 SYNC HDLC Dialing  
This setting provides V.25 bis messages in bit-synchronous format (for exam-  
ple HDLC, SDLC, X.25). The bit-synchronous format is the most commonly  
used by V.25 bis.  
This option specifies that the characters should be 7-bit ASCII, with the 8th bit  
ignored (it may be either 0 or 1).  
The first byte of each packet contains all ones (A = FF HEX), and the second  
byte of each packet (the C byte) is either 13 HEX or 03 HEX if not the final pack-  
et.  
V.25 SYNC BISYNC Dialing  
This setting allows for V.25 bis messages in byte synchronous format (BI-  
SYNC). V.25 bis specifies that the characters should be ASCII, 7 bits, and odd  
parity. This setting allows synchronous DTE which does not use HDLC to  
support serial in-band dialing.  
V.25 HDLC FLAG  
Configuring the ISU 128 for HDLC FLAG V.25 bis enables in-band dialing  
over a DTE interface using standard synchronous HDLC V.25 bis commands  
with 0x7E hex idle.  
Disabled  
This selection disables in-band dialing over the DTE interface.  
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Chapter 6. Configuration  
Auto Answer  
The ISU 128 auto answer parameter can be configured in one of three ways:  
Disabled, Enabled, or Dump all calls.  
Disabled  
When Disabled is selected, the ISU 128 will not automatically answer an in-  
coming call. The AT answer command (ATA) must be issued to the ISU 128  
before it accepts the incoming call. The ringing call can be dumped using the  
Hang up line command, or answered using the Answer Call command.  
These commands are listed under the Dial branch of the main tree. See the  
chapter Dial Options for more detail.  
Enabled  
When Enabled is selected, the incoming call is answered. If that call is a  
BONDING call and requires two B channels, the second call is answered. If  
the unit is configured for a call that uses only one B channel, such as 56 kbps  
or 64 kbps, the ISU 128 will not accept a second incoming call.  
Dump all calls  
When Dump all calls is selected, the ISU 128 will not accept any incoming  
calls. This keeps the line clear for outgoing calls.  
36  
ISU 128 User Manual  
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Chapter 6. Configuration  
Answer Tone  
The Answer tone option (shown in Figure 6-9) enables the transmission of a  
modem answer tone at the start of voice and audio calls. The purpose of this  
tone is to disable echo suppression and echo cancelling on the circuit in order  
to get a clear digital circuit. This may be necessary on some long distance cir-  
cuits. The specifics of the tone are 4 seconds, 2100 Hz at a -10 dB level, with  
phase reversals every 475 ms.  
1=Switch protocl  
2=Call type  
1=Dial Line  
3=Terminal ID  
1=No answer tone  
2=Incoming tone  
3=Outgoing tone  
4=Always tone  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=CONFIG  
4=Quick setup  
5=Remote config  
Figure 6-9  
Answer Tone Menu Tree  
No Answer Tone (Default)  
This option disables Answer tone on incoming calls.  
Incoming Tone  
This option enables Answer tone on incoming calls.  
Outgoing Tone  
This option enables Answer tone on outgoing calls.  
Always Tone  
This option enables Answer tone on either incoming or outgoing calls.  
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Chapter 6. Configuration  
Connect Timeout  
Connect Timout sets the length of time that the ISU 128 waits for a far-end unit  
to answer an outgoing call. These choices are illustrated in Figure 6-10.  
1=Switch protocl  
2=Call type  
1=Dial Line  
3=Terminal ID  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=CONFIG  
1=15 sec  
2=30 sec (default)  
3=1 Minute  
4=2 Minute  
5=4 Minute  
4=Quick setup  
5=Remote config  
Figure 6-10  
Connect Timeout Menu Tree  
Call Screening  
Call Screening allows the ISU 128 to answer all incoming calls (default) or  
only calls originating from phone numbers stored in the DIAL menu as stored  
numbers SN0 through SN9. See the section Front Panel Dialing Options, to re-  
view how to store numbers. Figure 6-11 illustrates the menu tree for setting  
call screening.  
1=Switch protocl  
2=Call type  
1=Dial Line  
3=Terminal ID  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
4=Dial options  
5=Auto answer  
6=Answer tone  
7=Connect Timout  
8=Call Screening  
3=CONFIG  
1=Answer any  
2=Ansr if SN0...9  
4=Quick setup  
5=Remote config  
Figure 6-11  
Call Screening Menu Tree  
When Call Screening is set to answer any numbers if stored in SN0 through  
SN9 (Ansr if SN0...9), an incoming call is not answered if the Call ID received  
from the switch does not match a stored number. Depending on the switch  
protocol, the Call ID may be presented in either a seven- or ten-digit format.  
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ISU 128 User Manual  
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Chapter 6. Configuration  
The ISU 128 displays the Call ID for all dumped calls in the Status buffer. See  
the section Status Buffer for more information on the Status buffer.  
Because different switches handle calls and Call ID differently,  
use the following procedure to determine if a seven or ten digit Call ID (phone  
number) should be stored:  
1. Select Ansr if SN0. . .9 under Call Screening.  
2. Store your seven digit number in SN0.  
3. Place a call to the ISU 128 with the stored number to determine whether it  
answers properly.  
4. If the ISU 128 does not answer the call, look at the Call ID message in the  
Status buffer. An explanation of Status buffer messages is located in the  
appendix Status Buffer Messages. More than likely, the Call ID number is a  
ten digit number  
5. Reenter the number in SN0 as it is displayed in the Call ID message and  
test Call Screening again.  
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ISU 128 User Manual  
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Chapter 6. Configuration  
LEASED LINE SERVICE  
This section explains how to configure the ISU 128 when using a 2B1Q leased  
digital service or a service that provides a permanent connection between end  
points. Figure 6-12 illustrates the menu tree for setting leased line.  
1=Dial Line  
1=Slave  
1=Netw. options  
2=DTE options  
3=Protocol  
2=Leased Line  
1=Clock mode  
2=Channel rate  
2=Master  
3=CONFIG  
1=64k  
2=128k  
4=Quick setup  
5=Remote config  
Figure 6-12  
Leased Line Menu Tree  
Selecting leased line configures the unit for leased line service or service that  
provides a permanent connection between end points such as limited distance  
modem.  
Follow this step-by-step procedure to configure the ISU 128 for Leased Line  
Clock mode and Channel rate.  
Clock Mode:Slave/Master  
By configuring the ISU 128 for Master timing, the ISU 128 can provide clock-  
ing for both ends of the phone line. This Master option is used at one end of a  
limited distance modem application, where two ISU 128 units are directly con-  
nected without the use of channel banks (see Figure 6-13). The far-end unit  
should be configured for Slave and it derives its clocking from the ISU 128  
configured as Master.  
18,000 Ft  
ISU 128  
ISU 128  
ENTER  
1
4
7
#
2
5
8
0
3
6
9
ENTER  
1
4
7
#
2
5
8
0
3
6
9
R
S
C
S
T
D
RD LD TR SR  
R
S
C
S
T
D
RD LD TR SR  
CANCEL  
CANCEL  
*
*
Mixed Gauge Wire  
ISU 128  
Leased 128K  
ISU 128  
Master  
DTE  
DTE  
Figure 6-13  
Limited Distance Modem Application  
40  
ISU 128 User Manual  
61202.029L2-1  
 
Chapter 6. Configuration  
If two ISU 128 units are connected through channel banks, both units should  
be configured for Slave mode (see Figure 6-14). To easily configure ISU 128s  
for this application, one unit can be optioned using Quick Setup, Ldm 128  
Master and the other using Quick Setup, Leased 128k sync. For more informa-  
tion, refer to the chapter Quick Setup.  
BIMUX DP  
or Equivalent  
BIMUX DP  
or Equivalent  
T1  
XXXXX  
XXXXXXXXX  
X X X X X  
X X X X X  
XXXXX  
X X X X X X X X X  
ISU 128  
ISU 128  
ENTER  
1
4
7
#
2
5
8
0
3
6
9
ENTER  
1
4
7
#
2
5
8
0
3
6
9
R
S
C
S
T
D
R
D
L
D
T
R
S
R
R
S
C
S
T
D
R
D
L
D
T
R
S
R
CANCEL  
CANCEL  
*
*
ISU 128  
ISU 128  
DTE  
DTE  
Figure 6-14  
Leased Application with Channel Banks  
Channel Rate  
In Leased Line operation, the data rate for the ISU 128 can be configured for  
64 kbps or 128 kbps. When 64 kbps is selected, only one bearer channel (B1) is  
used. When 128 kbps is selected both bearer channels (B1 and B2) are used.  
61202.029L2-1  
ISU 128 User Manual  
41  
 
Chapter 6. Configuration  
DTE OPTIONS  
The following procedure configures the DTE options for asynchronous and  
synchronous applications. Figure 6-15 and Figure 6-16 illustrate the menu  
trees for both asynchronous and synchronous operation.  
Ensure your DTE equipment is set for asynchronous operation before attempting to  
make an asynchronous call. Failure to do so will cause the call attempt to fail.  
1=Bit Rate  
2=Connector Type  
3=RTS Options  
1=Netw. options  
4=CTS Options  
1=Asynchronous  
2=DTE options  
3=CONFIG  
5=CD Options  
6=DTR Options  
7=DSR Options  
8=Flow Control  
9=Data Format  
2=Synchronous  
3=Protocol  
4=Quick setup  
5=Remote config  
Figure 6-15  
Asynchronous DTE Options Menu Tree  
1=Bit Rate  
2=Connector Type  
3=RTS Options  
4=CTS Options  
1=Netw. options  
2=DTE options  
3=Protocol  
1=Asynchronous  
2=Synchronous  
3=CONFIG  
5=CD Options  
6=DTR Options  
7=DSR Options  
8=Transmit Clock  
4=Quick setup  
5=Remote config  
Figure 6-16  
Synchronous DTE Options Menu Tree  
Bit Rate  
The Bit Rate can be set asynchronously for 300, 1200, 2400, 4800, 9600, 19200,  
38400, 57600, and 115200 bps.  
The Bit Rate can be set synchronously for 2400, 4800, 9600, 19200, 38400, 48000,  
56000, 64000, 112000, and 128000 bps.  
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ISU 128 User Manual  
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Chapter 6. Configuration  
Connector Type  
The ISU 128 can provide an EIA-232, RS-530, or V.35 interface to a DTE by se-  
lecting the desired connector type.  
RTS Options  
Selecting 1 MS delay causes the Clear-to-Send (CTS) signal to change states 1  
millisecond after the DTE Ready-to-Send (RTS) signal changes state. The 18  
MS delay causes the CTS signal to change state 18 milliseconds after the DTE  
RTS signal changes state.  
CTS Options  
Selecting Forced CTS causes the CTS signal on the DTE connector to be con-  
tinually asserted. Selecting Follows RTS causes the CTS signal to follow the  
state of the RTS lead.  
CD Options  
Selecting CD Forced on causes the carrier detect (CD) signal to always be as-  
serted. Selecting Normal causes the CD signal to be asserted when a call has  
been successfully established. Selecting Off with LOCD causes the CD signal  
to be disasserted for a period of 5 seconds, then reasserted at the termination  
of a call. Selecting Off with Link Down causes the CD signal to be disasserted  
when the U-interface is not present.  
DTR Options  
Selecting Ignore DTR causes the ISU 128 to disregard the state of the data ter-  
minal ready (DTR) pin. Cmd when Off forces the unit into the AT command  
processor mode when DTR is not asserted. To return on-line, DTR must be as-  
serted, followed by the AT0 command. Idle when Off forces the unit to end  
the current call when DTR is no longer asserted. Off>On dial #0allows one  
call attempt to be automatically established when the DTR signal goes from in-  
active to active. While DTR is active, front panel dialing is also possible.  
When DTR goes inactive, any outgoing call present is disconnected. Off>On  
dial #0uses the phone number in stored number register 0 to establish the call.  
To store a number for automatic dialing see the chapter Dialing Options. Se-  
lecting Dial #0 if Onallows calls to be automatically established when the  
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Chapter 6. Configuration  
DTR signal is in the active state. The unit attempts to establish a call using SN0  
until the call is established or DTR goes inactive. Selecting Answer if On only  
allows the unit to answer an incoming call if the DTR signal is asserted. Dial/  
Ans if On... allows the unit to dial Stored Number 0 or answer if DTR is assert-  
ed.  
DSR Options  
Selecting DSR forced on causes the Data Set Ready (DSR) signal on the DTE  
connector to always be asserted. Selecting OFF Idle+Test causes DSR to be  
disasserted if the network interface is in test or there is not an active call. OFF  
Link Down causes DSR to be disasserted if the network interface is disrupted.  
Flow Control (Asynchronous Data Format)  
Selecting Hardware Flow (as shown in Figure 6-17) causes the ISU 128 re-  
ceived data to be presented to the DTE interface only when RTS is asserted.  
Software Flow control uses Xon/Xoff to control data transferred between the  
DTE and the ISU 128. Selecting No Flow Ctrl disables flow control.  
1=Bit Rate  
2=Connector Type  
3=RTS Options  
1=Netw. options  
4=CTS Options  
1=Asynchronous  
2=DTE options  
3=CONFIG  
5=CD Options  
6=DTR Options  
7=DSR Options  
8=Flow Control  
9=Data Format  
2=Synchronous  
3=Protocol  
4=Quick setup  
5=Remote config  
1=Hardware Flow  
2=Software Flow  
3=No Flow Ctrl  
Figure 6-17  
Flow Control Menu Tree  
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Chapter 6. Configuration  
Data Format (Asynchronous)  
A frame consists of a start bit, 7 or 8 data bits, 0 or 1 parity bit, and 1 to 2 stop  
bits. The settings for Data Bits, Parity Bits, and Stop Bits are available as  
shown in Figure 6-18.  
1=Bit Rate  
2=Connector Type  
3=RTS Options  
1=Netw. options  
4=CTS Options  
1=Asynchronous  
2=DTE options  
3=CONFIG  
5=CD Options  
6=DTR Options  
7=DSR Options  
8=Flow Control  
9=Data Format  
2=Synchronous  
1=8 Data Bits  
2=7 Data Bits  
3=Protocol  
4=Quick setup  
5=Remote config  
1=Data Bits  
2=Parity Bits  
3=Stop Bits  
1=None  
2=Odd  
3=Even  
1=1 Stop bit  
2=1.5 Stop bits  
3=2 Stop bits  
Figure 6-18  
Data Format Menu Tree  
Transmit Clock (Synchronous Data Format)  
Selecting the Normal option causes the ISU 128 to be the synchronous DTE in-  
terface transmit timing source. Transmit data is timed from the transmit clock  
provided by the ISU 128 on the DTE connector. Normal clock is the normal  
mode of operation for the ISU 128.  
With the External option selected, the ISU 128 slaves to an external transmit  
timing source. The external clock is provided to the ISU 128 by the external  
transmit clock signal at the DTE connector. This signal is echoed by the ISU  
128 to the transmit clock signal on the DTE connector.  
This option provides for situations where equipment connected to the ISU 128  
DTE connector cannot slave to the ISU 128 provided clock. The ISU 128 uses  
the U-interface as the frequency standard when it must provide a synchronous  
receive or transmit clock. The externally provided clock must be of the same  
average frequency as the clock that the ISU 128 would provide if internal clock  
were selected. If this is not the case, then bit errors may occur.  
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Chapter 6. Configuration  
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Chapter 7  
Protocol Options  
PROTOCOL OPTIONS  
The ISU 128 communicates with many different types of telecommunication  
equipment including other ISU 128s, ISDN terminal adapters, Switched 56  
DSUs, BONDING-compatible inverse multiplexers, and V.34 (1202029L3 only)  
compatible analog modems. Communicating between such diverse types of  
equipment requires the use of various rate adaptation protocols to support  
various bit rates and DTE settings. Figure 7-1 illustrates the menu tree for set-  
ting protocol options. The ISU 128 supports the following rate adaptation pro-  
tocols:  
•
•
•
•
•
Clear Channel (no rate adaption protocol)  
BONDING mode 1 (Bandwidth on Demand Interoperability Group)  
CCITT V.120  
CCITT V.110  
V.34 (for communicating with analog modems)  
V.34 is only available in PN 1202029L3  
•
DSU 56.7 Async (for communication with ADTRAN DSUs)  
TLINK (Dial Switched 2-wire 56 or Datapath DSU)  
SAP (Simple ADTRAN Protocol)  
•
•
•
•
FALLBACK  
Point-to-point protocol (PPP) asynchronous to synchronous conversion  
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Chapter 7. Protocol Options  
1=Clear Channel  
2=BONDING mode 1  
3=V.120  
1=Netw. options  
2=DTE options  
3=Protocol  
3=CONFIG  
4=V.34  
4=Quick setup  
5=Remote config  
5=V.110  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
9=FALLBACK  
0=PPP asyn-sync  
Figure 7-1  
Protocol Menu Tree  
See the section Recommended Operating Protocols and Table 1-B in Chapter 1 for  
more information on recommended modes of operation.  
The desired protocol may be selected with AT commands at the DTE port or  
from the ISU 128 front panel. A description of each protocol follows.  
Clear Channel  
Clear Channel provides the entire bearer channel to the DTE without regard  
to data format or protocol. This provides a rate adaptation at or near the ISDN  
circuit rate. The primary usage for Clear Channel in the dial line mode is for  
56 kbps and 64 kbps synchronous. It is useful when the DTE performs its own  
internal synchronous protocol/rate adaptation or the ISU 128 is calling a 4-  
wire Switched 56 DSU. In the leased line mode, Clear Channel can provide  
synchronous bit rates of 56 kbps, 64 kbps, 112 kbps, and 128 kbps.  
BONDING Mode 1  
The BONDING mode 1 protocol allows the ISU 128 to communicate at bit  
rates in excess of 64 kbps to a maximum of 128 kbps. BONDING provides  
high-speed communication between ISU 128s, ISDN TE/TAs, and inverse  
multiplexing equipment supporting the BONDING protocol. The protocol al-  
lows use of both synchronous and asynchronous bit rates. When the ISU 128  
uses the BONDING mode 1 protocol, it must make two separate ISDN phone  
calls to seize control of both ISDN bearer channels. The protocol corrects any  
delays existing between the two bearer channels and presents a single high  
speed data channel to the DTE. For successful high-speed operation, both the  
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Chapter 7. Protocol Options  
near- and far-end DCE need to be configured to use the BONDING mode 1  
protocol. Also, if the second B channel number is different from the first B  
channel, it is important that the 7-digit LDN is programmed in the answering  
unit. The BONDING mode 1 protocol negotiation phase has numerous timers  
to allow for transmission delays due to satellite hops, international calls, etc.  
The timers may be adjusted if necessary by entering into the BONDING mode  
1 submenu. Figure 7-2 illustrates the menu path for setting the timers.  
1=TXINIT  
2=TXFA  
1=Clear Channel  
3=TXADD01  
1=Netw. options  
2=DTE options  
3=Protocol  
2=BONDING mode 1  
3=V.120  
4=TXDEQ  
3=CONFIG  
5=TANULL  
4=V.34  
6=TCID  
4=Quick setup  
5=Remote config  
5=V.110  
7=BONDING Method 1=ADTRAN Only  
2=Multivendor  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
9=FALLBACK  
0=PPP asyn-sync  
Figure 7-2  
BONDING Mode 1 Protocol Menu Tree  
The timers are defined as follows:  
TXINIT  
This option specifies the length of time the originating endpoint attempts to  
detect the BONDING negotiation pattern from the answering endpoint before  
deciding the BONDING call has failed. In general, this timer value should be  
left at the factory default setting of 10 seconds. Values of 1, 2, 5, 10 (default),  
20, 50, 100, and 200 seconds may be selected.  
TXFA  
This option specifies the length of time both endpoints attempt to detect the  
BONDING frame pattern when a call is connected before deciding the BOND-  
ING call has failed. This timer value should be left at the factory default setting  
of 10 seconds. However, when interoperating with other manufacturers’  
BONDING equipment, it may be necessary to lengthen this timer so that it  
matches TXADD01. Values of 1, 2, 5, 10 (default), 20, 50, 100, and 200 seconds  
may be selected.  
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Chapter 7. Protocol Options  
TXADD01  
This option specifies the length of time both endpoints wait for the additional  
call to be connected at the end of negotiation before deciding the BONDING  
call has failed. The factory default setting of 20 seconds will be sufficient for  
most calls to go through, although when dialing overseas it may be necessary  
to lengthen this timer to allow for slower call routing. Values of 1, 2, 5, 10, 20,  
50 (default), 100, and 200 seconds may be selected.  
TXDEQ  
This option specifies the length of time both endpoints attempt to equalize the  
network delay between the bearer channels before deciding the BONDING  
call has failed. The default setting is 50 seconds. Values of 1, 2, 5, 10, 20, 50  
(default), 100, and 200 seconds may be selected.  
TANULL  
This option specifies the length of time the answering endpoint attempts to de-  
tect the BONDING negotiation pattern from the originating endpoint before  
aborting to clear channel mode. In general, this timer value should be left at  
the factory default setting of 10 seconds. However, it may be necessary to  
shorten this timer, if the DTE equipment connected to the ISU also has timer  
constraints for completing non-BONDING parameter negotiation. Values of  
1, 2, 5, 10 (default), 20, 50, 100, and 200 seconds may be selected.  
TCID  
This option specifies the length of time both endpoints attempt to negotiate an  
agreeable value for bearer channels and channel capacities before deciding the  
BONDING call has failed. This timer default setting is 5 seconds. Values of 1,  
2, 5 (default), 10, 20, 50, 100, and 200 seconds may be selected.  
V.120  
The V.120 protocol is a CCITT compliant rate adaption method which pro-  
vides DTE service between the ISU 128 and other V.120 compliant devices at  
rates less than the 64 kbps ISDN bearer channel rate. V.120 supports synchro-  
nous and asynchronous DTE rates. See the section Recommended Operating  
Modes and Table 1-B in Chapter 1 for available V.120 rates. Figure 7-2 illus-  
trates the menu path for selecting V.120.  
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Chapter 7. Protocol Options  
V.110  
The V.110 protocol is a CCITT compliant rate adaption method which pro-  
vides DTE service between the ISU 128 and other V.110 compliant devices.  
V.110 supports synchronous and asynchronous DTE rates. See the section  
Recommended Operating Modes and Table 1-B in Chapter 1 for available V.110  
rates. Figure 7-2 illustrates the menu path for selecting V.110.  
V.34  
The V.34 protocol allows the ISU to originate and receive calls to analog mo-  
dems on POTS lines. The V.34 modem only supports asynchronous DTE rates.  
To place an outgoing call to an analog modem, the call type must be changed  
to Audio. See Call Type in Chapter 6 to change call types. Figure 7-3 illustrated  
the menu path for selecting the V.34 modem operational parameters.  
The ISU 128 with optional V.34 modem (part number 1202029L3) must be used for  
operation of this protocol.  
Error Control  
This option sets the type of error control to be negotiated with the far-end mo-  
dem during train-up. Normal turns all error control off and makes allowances  
for flow control. Reliable MNP uses MNP error control. If the far end does  
not support MNP then the call is terminated. When Auto-Rel MNP is select-  
ed, the ISU 128 attempts to use MNP error control. If the far end does not use  
MNP then normal operation is used. Force LAPM allows only LAPM (V.42)  
error corrected calls to connect. Force MNP allows only MNP error corrected  
calls to connect.  
1=Clear Channel  
1=Netw. options  
2=BONDING mode 1  
1=Normal  
2=DTE options  
3=CONFIG  
3=V.120  
2=Direct  
3=Protocol  
1=Error Ctrl  
4=V.34  
3=Reliable MNP  
4=Auto-Rel MNP  
5=Force LAPM  
6=Force MNP  
4=Quick setup  
5=Remote config  
2=Compression  
3=MNP Blk Size  
5=V.110  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
9=FALLBACK  
0=PPP asyn-sync  
Figure 7-3  
V.34 Error Control Menu Tree  
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Chapter 7. Protocol Options  
Compression  
No Compression turns off the MNP5 compression algorithms in the ISU 128.  
Compress MNP5 enables MNP5 data compression. Compress V42 enables  
V.42 bis data compression. Compress V42/MNP5 allows the 128 to negotiate  
MNP5 or V.42 bis compression.  
1=Clear Channel  
1=Netw. options  
2=BONDING mode 1  
1=No Compression  
2=DTE options  
3=CONFIG  
3=V.120  
2=Compress MNP5  
3=Compress V42  
4=Comp V42 MNP5  
3=Protocol  
1=Error Ctrl  
4=V.34  
4=Quick setup  
5=Remote config  
2=Compression  
3=MNP Blk Size  
5=V.110  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
9=FALLBACK  
0=PPP asyn-sync  
Figure 7-4  
V.34 Compression Menu Tree  
Microcom™ Network Protocol Block Size (MNP® Blk)  
When error control is enabled, this option sets the amount of data sent in a sin-  
gle packet during MNP error-controlled stream operation. Options available  
are 64, 128, 192, and 256 bytes.  
1=Clear Channel  
1=Netw. options  
2=BONDING mode 1  
2=DTE options  
3=CONFIG  
3=V.120  
3=Protocol  
1=Error Ctrl  
4=V.34  
4=Quick setup  
5=Remote config  
2=Compression  
3=MNP Blk Size  
5=V.110  
1=64 bytes  
2=128 bytes  
3=192 bytes  
4=256 bytes  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
9=FALLBACK  
0=PPP asyn-sync  
Figure 7-5  
V.34 MNP Block Size Menu Tree  
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Chapter 7. Protocol Options  
DSU 57.6 ASYNC  
The DSU 57.6 ASYNC or DSTOP protocol allows the ISU 128 to communicate  
asynchronously at 57.6 kbps with ADTRAN 2- and 4-wire Switched 56 DSU  
products. In addition, the ISU 128 will communicate with other ISUs over dial  
and leased connections using this protocol. Figure 7-1 illustrates the menu  
path for setting the DSU 57.6 ASYNC protocol.  
T-Link  
The T-Link protocol allows the ISU 128 to communicate with 2-wire Switched  
56 DataPath Data Units (DUs) such as the ADTRAN DSU III 52W. The T-Link  
protocol performs two functions:  
•
The T-link protocol adapts DTE data subrates of 64 kbps to the 64 kbps  
bandwidth of the ISDN bearer channel.  
•
For asynchronous and synchronous DTE rates up to 19.2 kbps, T-Link  
transmits the status of the DCE-DTE EIA leads to facilitate flow control  
and maintenance.  
In addition to 2-wire Switched 56 DataPath DUs, the ISU 128 can communicate  
with any other device that uses the T-Link protocol. Figure 7-1 shows the  
menu path for selecting T-Link.  
Simple ADTRAN Protocol (SAP)  
Simple ADTRAN Protocol (SAP) is a rate adaption method providing DTE  
service between ISU 128 units at a sub 64 kbps ISDN bearer channel rate. Se-  
lecting this menu item causes the ISU 128 to use SAP protocol.  
The primary usage for SAP is general purpose asynchronous rate adaption in  
a dial-up or leased environment. SAP only operates on a 64 kbps data link.  
See Figure 7-2 for the menu path to select SAP.  
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Chapter 7. Protocol Options  
FALLBACK  
The FALLBACK asynchronous rate adaption protocol provides the capability  
to automatically establish calls with other ISDN terminal adapters, Switched  
56 DSUs, V.34 modems (optional), as well as other ISUs using a single config-  
uration. To communicate with analog modems, the ISU 128 with V.34 modem  
option (part numbers 1202029L3) must be used.  
The ISU 128 must be optioned as follows for FALLBACK operation:  
•
•
Any asynchronous bit rate up to 115.2 kbps which is supported by the  
DTE.  
Flow control must be enabled and supported by the DTE.  
FALLBACK supports the following protocols based on the call type: BOND-  
ING Mode 1, V.120, T-Link, and V.34.  
When answering calls, the ISU 128 uses the incoming call type to determine  
which rate adaption protocols to support. See Table 7-A for the call type and  
the supported rate adaption protocols.  
Table 7-A  
Rate Adaption Protocols  
Rate Adaption  
Protocols Supported  
Call Type  
Typical Units Supported  
Data 64k  
BONDING Mode 1  
ISUs  
V.120  
PPP  
ISDN TAs  
PPP compatible bridges/routers  
Data 56k  
V.120  
T-Link  
PPP  
ISDN TAs  
2-Wire Switched-56 DSUs  
PPP compatible bridges/routers  
Speech or Audio  
V.34  
V.34 compatible modems  
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Chapter 7. Protocol Options  
When originating calls to unknown units, the ISU begins protocol selection  
based on the local call type. Data 64k is used for FALLBACK selected from  
Quick Setup menu. Upon connection at 64k call type, BONDING, V.120, and  
PPP are attempted. If connection is not made at 64k, the ISU 128 attempts an-  
other call at 56k call type. If connection is made at 56k, then V.120, T-Link, and  
PPP are attempted. If connection is not made at 56k, then an audio call type is  
attempted, provided the ISU 128 with the V.34 modem option is used. If the  
ISU connects the audio call type, the V.34 protocol is attempted for V.34 com-  
patible modems. Once a call connects, if the protocol cannot be negotiated, the  
protocol is negotiated as specified by S11 register (default is DSTOP). If this  
protocol fails, the call is disconnected.  
If FALLBACK fails to determine which protocol is running, the user has the  
option to select which protocol will run. Figure 7-6 illustrates the FALLBACK  
default settings.  
1=Clear Channel  
1=Netw. options  
2=BONDING mode 1  
2=DTE options  
3=CONFIG  
3=V.120  
3=Protocol  
4=V.34  
4=Quick setup  
5=Remote config  
5=V.110  
6=DSU 57.6 ASYNC  
7=T-LINK  
1=Clear Channel  
2=BONDING Mode 1  
3=V.120  
8=SAP  
9=FALLBACK  
0=PPP asyn-sync  
1=Fallback Def.  
4=V.34  
5=V.110  
6=DSU 57.6 ASYNC  
7=T-LINK  
8=SAP  
9=PPP asyn-sync  
Figure 7-6  
FALLBACK Menu Tree  
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Chapter 7. Protocol Options  
Point-to-Point (PPP) Async-to-Sync  
PPP provides a standard method for transporting multi-protocol datagrams  
over point-to-point links. The ADTRAN PPP async-sync protocol allows the  
®
ISU 128 and a PC or Macintosh running PPP software, to communicate with  
a PPP-compatible bridge or router. The PPP async-sync protocol complies  
with Internet Engineering Task Force (IETF) RFC 1662. The menu path to se-  
lect PPP is shown in Figure 7-7.  
The asynchronous control character map (ACCM) option is scanned during  
the negotiation. When the ACCM option is seen in a configure ACK link con-  
trol packet, it is adopted by the ISU 128. In addition, when the ACCM option  
is not seen in the configure-request packet from the network, the ISU 128 adds  
it to the packet.  
1=Clear Channel  
1=Netw. options  
2=BONDING mode 1  
2=DTE options  
3=CONFIG  
3=V.120  
3=Protocol  
4=V.34  
4=Quick setup  
5=Remote config  
5=DSU 57.6 ASYNC  
6=T-LINK  
7=SAP  
8=FALLBACK  
9=PPP asyn-sync  
1=METHOD  
1=PPP  
2=Multilink PPP  
3=PPP w/ Comp  
Figure 7-7  
PPP Menu Tree  
Point-to-Point Protocol (PPP)  
The ISU 128 is configured for PPP from the protocol options of the configura-  
tion menu by selecting 1=PPP or by setting S-register S27 to a value of 0. Fig-  
ure 7-6 illustrates the menu path for setting PPP, Multilink PPP, and PPP w/  
Comp.  
Multilink Point-to-Point Protocol (MP)  
Multilink PPP is an extension of point-to-point protocol and is a method for  
splitting and recombining data packets across multiple logical data links.  
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Chapter 7. Protocol Options  
The ISU 128 is configured for multilink PPP from the protocol options of the  
configuration menu by selecting 2=Multilink PPP or by setting S-register S27  
to a value of 1. In this mode, the ISU 128 dials a second number to establish a  
second point-to-point link. Once the second link is established, multilink PPP  
is performed over both B-channels.  
The phone number for the second call should be placed in stored number 1  
(SN1). If no number is stored in SN1, the same phone number is dialed to es-  
tablish the second link.  
PPP with Compression  
The ISU 128 is configured for PPP with compression from the protocol options  
of the the configuration menu by selecting 3=PPP w/Comp or by setting S-reg-  
ister S27 to a value of 2.  
When setup for PPP with compression, the ISU 128 will negotiate the compres-  
sion control protocol (CCP) with the network PPP peer. If STAC™ compres-  
sion is successfully negotiated with the peer, data packets from the DTE are  
compressed before being sent out through the network. Likewise, compressed  
packets from the network are decompressed before being transmitted through  
the DTE.  
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Chapter 7. Protocol Options  
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Chapter 8  
Quick Setup  
QUICK SETUP CONFIGURATION  
To configure the DTE Options quickly and easily, the Quick Setup menu is  
available to automatically set up the most common DTE configurations (Fig-  
ure 8-1). For fine-tuning a particular application and DTE settings, see the sec-  
tion DTE Options for Asynchronous and Synchronous Operation in Chapter 6 for  
a step-by-step procedure for configuration of the DTE Options.  
1=Dial 56K sync  
1=Netw. options  
2=Dial 64K sync  
2=DTE options  
3=CONFIG  
3=Dial 112K sync  
3=Protocol  
4=Dial 128K sync  
4=Quick setup  
5=Dial PPP  
5=Remote config  
6=V34 115.2 async  
1=Leased 128k  
7=Dial 57.6 asyn  
2=Ldm 128 Master  
8=Dial 115.2 asy  
3=TBD  
9=Fallback 57.6k  
4=TBD  
0=More  
5=TBD  
6=TBD  
7=TBD  
Figure 8-1  
Quick Setup Menu Tree  
Option 1=DIAL 56K sync will always flash upon entry of the Quick Setup Menu re-  
gardless of previous configuration selections.  
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Chapter 8. Quick Setup  
Quick Setup  
To assist in configuring the DTE options for the ISU 128, ten common config-  
urations are preset in Quick Setup. These include:  
•
•
•
•
•
•
Synchronous dial operation for 56, 64, 112, and 128 kbps  
Asynchronous dial operation for 57.6, and 115.2 kbps  
128 kbps Leased service  
128 kbps Limited Distance Modem using Master Clocking  
V.34 modem service  
Fallback 57.6  
In the following descriptions, an asterisk (*) following the option indicates the option  
requires ISDN switch protocol to be configured. Multipoint lines will also require  
SPID1 & LDN1. See the chapter Dial Options.  
Dial 56K sync*  
When the ISU 128 is configured for Dial 56K sync service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
Automatic answering...................................................... Enabled  
ISDN call type .................................................................. 56 kbps data  
Data protocol.................................................................... Clear Channel  
DTE mode ......................................................................... Synchronous  
DTE connector bit rate .................................................... 56 kbps  
DTE flow control.............................................................. none  
RTS line ............................................................................. 1 ms delay  
CTS line ............................................................................. Forced on  
Transmit data clock ......................................................... Normal clock source  
V.54 Loopbacks ................................................................ Accepted  
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Chapter 8. Quick Setup  
Dial 64K sync*  
When the ISU 128 is configured for Dial 64K sync service the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
Automatic answering...................................................... Enabled  
ISDN call type .................................................................. 64 kbps data  
Data protocol .................................................................... Clear Channel  
DTE mode ......................................................................... Synchronous  
DTE connector bit rate .................................................... 64 kbps  
DTE flow control.............................................................. none  
RTS line.............................................................................. 1 msec delay  
CTS line ............................................................................. Forced on  
Transmit data clock ......................................................... Normal clock source  
V.54 Loopbacks ................................................................ Accepted  
Dial 112K sync*  
When the ISU 128 is configured for Dial 112K sync service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
Automatic answering...................................................... Enabled  
ISDN call type .................................................................. 56 kbps data  
Data protocol .................................................................... BONDING mode 1  
DTE mode ......................................................................... Synchronous  
DTE connector bit rate .................................................... 112 kbps  
DTE flow control.............................................................. none  
RTS line.............................................................................. 1 ms delay  
CTS line ............................................................................. Forced on  
Transmit data clock ......................................................... Internal clock source  
BONDING timer TXINIT ............................................... 10 seconds  
BONDING timer TXFA................................................... 10 seconds  
BONDING timer TXADD01........................................... 50 seconds  
BONDING timer TXDEQ ............................................... 50 seconds  
BONDING timer TANULL ............................................ 10 seconds  
BONDING timer TCID ................................................... 5 seconds  
V.54 Loopbacks ................................................................ Accepted  
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Chapter 8. Quick Setup  
Dial 128K sync*  
When the ISU 128 is configured for Dial 128K sync service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
Automatic answering...................................................... Enabled  
ISDN call type .................................................................. 64 kbps data  
Data protocol.................................................................... BONDING mode 1  
DTE mode ......................................................................... Synchronous  
DTE connector bit rate .................................................... 128 kbps  
DTE flow control.............................................................. None  
RTS line ............................................................................. 1 ms delay  
CTS line ............................................................................. Forced on  
Transmit data clock ......................................................... Internal clock source  
BONDING timer TXINIT ............................................... 10 seconds  
BONDING timer TXFA................................................... 10 seconds  
BONDING timer TXADD01........................................... 50 seconds  
BONDING timer TXDEQ ............................................... 50 seconds  
BONDING timer TANULL ............................................ 10 seconds  
BONDING timer TCID ................................................... 5 seconds  
V.54 Loopbacks ................................................................ Accepted  
Dial PPP*  
When the ISU 128 is configured for Dial PPP service, the following parameters  
are automatically preset:  
Service type....................................................................... ISDN dial line  
ISDN call type .................................................................. 64 kbps data  
Data Protocol.................................................................... PPP asyn-sync  
DTE mode ......................................................................... Asynchronous  
Data Bits ............................................................................ 8  
Parity Bits.......................................................................... None  
Stop Bits............................................................................. 1  
DTE connector bit rate .................................................... Hardware  
DTE flow control.............................................................. None  
RTS line ............................................................................. 1 msec delay  
CTS line ............................................................................. Follow RTS  
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Chapter 8. Quick Setup  
V34 115.2 async*  
When the ISU 128 is configured for V34 115.2 async service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
ISDN call type .................................................................. Audio  
Data Protocol .................................................................... V.34  
DTE mode ......................................................................... Asynchronous  
Data Bits ............................................................................ 8  
Parity Bits.......................................................................... None  
Stop Bits............................................................................. 1  
DTE connector bit rate .................................................... 115.2 kbps  
DTE flow control.............................................................. Hardware  
RTS line.............................................................................. 1 msec delay  
CTS line ............................................................................. Follows RTS  
Error Control .................................................................... Auto-reliable  
Compression..................................................................... Compress V42/MNP5  
MNP block size ................................................................ 256 bytes  
This option is only used with the ISU 128 with V.34 modem option (part numbers  
1202029L3).  
Dial 57.6 asyn*  
When the ISU 128 is configured for Dial 57.6 asyn service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
ISDN call type .................................................................. 64 kbps data  
Data Protocol .................................................................... V.120  
DTE mode ......................................................................... Asynchronous  
Data Bits ............................................................................ 8  
Parity Bits.......................................................................... None  
Stop Bits............................................................................. 1  
DTE connector bit rate .................................................... 57.6 kbps  
DTE flow control.............................................................. None  
RTS line.............................................................................. 1 msec delay  
CTS line ............................................................................. Forced on  
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Chapter 8. Quick Setup  
Dial 115.2 asyn*  
When the ISU 128 is configured for Dial 115.2 asyn service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... ISDN dial line  
ISDN call type .................................................................. 64 kbps data  
Data Protocol.................................................................... BONDING mode 1  
DTE mode ......................................................................... Asynchronous  
Data Bits ............................................................................ 8  
Parity Bits.......................................................................... None  
Stop Bits............................................................................. 1  
DTE connector bit rate .................................................... 115.2 kbps  
DTE flow control.............................................................. Hardware  
RTS line ............................................................................. 1 msec delay  
CTS line ............................................................................. Follows RTS  
Fallback 57.6k*  
When the ISU 128 is configured for Fallback 57.6k service, the following pa-  
rameters are automatically preset:  
Service type....................................................................... Dial line  
Automatic answering...................................................... yes  
ISDN call type .................................................................. 64 kbps data  
Data Protocol.................................................................... Fallback  
DTE mode ......................................................................... Asynchronous  
Data Bits ............................................................................ 8  
Parity Bits.......................................................................... None  
Stop Bits............................................................................. 1  
DTE connector bit rate .................................................... 57.6 kbps  
DTE flow control.............................................................. Hardware  
RTS line ............................................................................. 1 msec delay  
CTS line ............................................................................. Follows RTS  
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Chapter 8. Quick Setup  
More  
More takes the user into the following level of choices:  
Leased 128K  
When the ISU 128 is configured for Leased 128K service the following param-  
eters are automatically preset:  
Service type....................................................................... Leased Line  
Network clock source...................................................... Slave  
Channel rate...................................................................... 128K  
Data Protocol .................................................................... Clear Channel  
DDS loopbacks enabled .................................................. Yes  
DTE mode ......................................................................... Synchronous  
DTE connector bit rate .................................................... 128 kbps  
DTE flow control.............................................................. none  
RTS line.............................................................................. 1 msec delay  
CTS line ............................................................................. Forced on  
Transmit data clock ......................................................... Normal clock source  
Ldm 128 Master  
When the ISU 128 is configured for a point-to-point application such as a lim-  
ited distance modem (LDM) arrangement, the Ldm 128 Master option auto-  
matically presets the following parameters:  
Service type....................................................................... Leased Line  
Network clock source...................................................... Master  
Channel rate...................................................................... 128K  
Data Protocol .................................................................... Clear Channel  
DDS loopbacks enabled .................................................. Yes  
DTE mode ......................................................................... Synchronous  
DTE connector bit rate .................................................... 128 kbps  
DTE flow control.............................................................. none  
RTS line.............................................................................. 1 msec delay  
CTS line ............................................................................. Forced on  
Transmit data clock ......................................................... Normal clock source  
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Chapter 8. Quick Setup  
Factory Setup  
This option restores the ISU 128 to the factory default setup:  
Service type................................................................ISDN dial line  
ISDN switch protocol...............................................AT&T 5ESS  
ISDN call type ...........................................................64 kbps data  
Dialing Mode.............................................................Front Panel  
Data protocol.............................................................Clear Channel  
DTE connector bit rate .............................................64 kbps  
DTE flow control.......................................................none  
RTS line ......................................................................Forced on  
CTS line ......................................................................Forced on 1 msec after RTS  
CD line........................................................................Turned on when call is up  
DSR line......................................................................Forced on  
Transmit data clock ..................................................Internal clock source  
BONDING timer TXINIT ........................................10 seconds  
BONDING timer TXFA............................................10 seconds  
BONDING timer TXADD01....................................10 seconds  
BONDING timer TXDEQ ........................................50 seconds  
BONDING timer TANULL .....................................50 seconds  
BONDING timer TXID ............................................5 seconds  
AT Commands Escape character............................+  
End-of-Line character value....................................13  
Line Feed character value........................................10  
Backspace character value.......................................8  
Transmit Data Clock.................................................Normal clock source  
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Chapter 9  
Dial Options  
DIALING OPTIONS  
Selecting 4=DIAL or pressing the #(pound) key from the Current Status menu  
displays the front panel available dialing options. (See Figure 9-2.) Access the  
VT 100 terminal dial options screen (Figure 9-1) by pressing Ctl-D from any  
screen. The dial options are only available when the ISU is configured for Dial  
Line operation (not Leased Line).  
Figure 9-1  
VT 100 Terminal Dial Options Screen  
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Chapter 9. Dial Options  
1=Hang up line  
2=Dial number  
3=Redial last #  
4=Answer Call  
5=Dial stored #  
6=Store/Review #  
4=DIAL  
Figure 9-2  
Dial Menu Tree  
Hang Up Line  
Terminates current call.  
Dial Number  
Enter and dial a number from the keypad. If an error is made while entering a  
number, press the Down arrow to correct the mistake. Press Cancel twice con-  
secutively to exit this menu item without dialing a number. Press Enter to dial  
the number and save as stored number 9 for redialing purposes.  
Redial Last Number  
Redial the last number called (or attempted). This number is saved as stored  
number 9 from the last attempted phone call.  
Answer Call  
Selectively answer incoming calls when Auto Answer is configured for dis-  
able. (Auto Answer is described in the section Auto Answer in Chapter 6.)  
Dial Stored Number  
Dial one of ten stored phone numbers. The Up and Down arrows permit view-  
ing and selecting of stored number. Press Enter to dial the number and save as  
stored number 9 (SN9) for redial purposes.  
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Chapter 9. Dial Options  
Store/Review Number  
Enter and review stored numbers. Press the Up or Down arrow to scroll  
through the 10 stored numbers (SN0 - SN9). To store a number, scroll to the  
desired stored number location, enter the number to be stored, and press Enter  
to save the number. If a mistake is made, use the Up and Down arrows to edit  
the number. Press Enter to save the number and exit. Press Cancel to exit with-  
out changing the number.  
The Dial Options Menu must be exited after dialing in order for CD (carrier detect)  
to be activated.  
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Chapter 10  
Remote Configuration  
Remote Configuration  
Remote Configuration allows configuration and testing of a remote unit by  
calling the remote unit from a local unit. The remote unit can be configured  
using AT commands, the Front Panel, or the VT 100 terminal interface.  
There are six items that cannot be set through remote configuration. The items  
are Dial Line Mode, SPID(s), LDN(s), Switch Type, Quick Setup, and Factory  
Default.  
Configuring with AT Commands  
A remote unit can be configured by issuing an ATD command with the phone  
number of the remote unit plus a dial string modifier. The configuration com-  
mand syntax is:  
ATD nnnnnnn#6#yyyyyy  
Where nnnnnnn is the remote number to call, and yyyyyy is a password of up  
to six digits.  
After the connection is established, AT commands issued to the local unit are  
sent to the remote unit and executed. The remote unit sends response back to  
the local unit which then sends the response out of the DTE interface connec-  
tor. See the appendices AT Commands and S-Registers of the ISU 128 manual  
for a complete list of commands.  
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Chapter 10. Remote Configuration  
Configuring and Testing with the Front Panel or  
VT 100 Terminal  
The menu path to follow to select remote configuration on the Front Panel is  
shown in Figure 10-1.  
1=Netw. options  
2=DTE options  
3=CONFIG  
3=Protocol  
4=Quick setup  
5=Remote config  
1=Cfg. Rmt. Unit  
2=Set Password  
3=Loopback remote 1B  
4=Loopback remote 2B  
Figure 10-1  
Remote Configuration Menu Path  
When using the VT 100 terminal interface, select the main menu option Cfg.  
Rmt. Unit. The Remote Configuration screen appears as shown in Figure 10-2.  
Figure 10-2  
Remote Configuration Screen  
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Chapter 10. Remote Configuration  
Configure Remote Unit  
This option allows configuration of a remote ISU 128. The Front Panel will dis-  
play a prompt for the remote number to dial. Enter a number and press Enter  
to continue. A prompt for the remote password is displayed. Enter up to six  
digits for the password to access the remote unit and press Enter to continue.  
The Front Panel displays status information about the call. When a connection  
is established, the Front Panel will display information as if it were the remote  
unit. If the connection was not successful, the Front Panel displays informa-  
tion for the local unit connection. Pressing Cancel anytime up to this point  
cancels the call. Pressing Cancel at the first remote display screen or selecting  
Hang up line disconnects the call.  
Figure 10-2 illustrates the VT 100 terminal screen when Cfg. Rmt. Unit is se-  
lected from the main menu. Enter the remote number to call and press Enter.  
When prompted, enter the password and press Enter. If a password has not  
been set for accessing the remote unit, press Enter. The VT 100 terminal will  
first display the Status Menu screen as it attempts to connect to the remote  
unit. Once successfully connected, the terminal will change back to the Con-  
figuration Menu screen and display remote information as if the remote unit  
were connected to the VT 100 terminal. Figure 10-3 illustrates the terminal  
screen when connected to a remote ISU 128. The call may be terminated by se-  
lecting Hang up line from the Dial menu.  
Figure 10-3  
Remote Unit Configuration Screen  
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Chapter 10. Remote Configuration  
The Front Panel can only be used to configure other ISU devices with front panels. AT  
commands and the VT 100 terminal can be used to configure any ISU device that sup-  
ports remote configuration, such as the Express XR/XRT and the ISU 2x64 Rack-  
mount.  
Remote Testing  
Two tests may be performed from the local unit before connecting to the re-  
mote unit. Figure 10-4 illustrates the menu path for choosing Loopback Re-  
mote 1B and Loopback Remote 2B from the Test menu on the front panel.  
1=Loopback DTE  
2=Loopback Netw.  
2=TEST  
3=Loopback Proto  
4=Loopback Remote  
5=Test Remote  
6=Lpbk Disable  
7=NEBE/FEBE  
0=Software Ver  
Figure 10-4  
Test Menu Path  
Loopback Remote 1B  
The Lpbk Remote 1B option allows a local unit to call, loopback, and BERT  
test a remote unit on one B-channel if both the local and remote units are con-  
figured for Fallback protocol. The Front Panel and VT 100 terminal will  
prompt for the remote number to dial. When a connection is established, error  
information is displayed. Press 1) Exit Test or Escape to exit the test. Figure  
10-5 illustrates the VT 100 terminal while testing Loopback Remote 1B.  
Loopback Remote 2B  
The Lpbk Remote 2B option allows a local unit to call, loopback, and BERT  
test a remote unit on two B-channels if both the local and remote units are con-  
figured for Fallback protocol. The Front Panel and VT100 terminal will  
prompt for the remote number to dial. When a connection is established, error  
information will be displayed. Press 1) Exit Test or Escape to exit the test.  
Set Password  
The Set Password option allows the user to store a password up to six digits  
for remote configuration access. If a password is entered, any other unit used  
to configure this unit remotely must send a password matching the stored  
password. If passwords do not match, the remote configuration fails to  
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Chapter 10. Remote Configuration  
connect. The screen from a VT 100 terminal is illustrated in Figure 10- 6. To  
set the password, choose Set Password from the Main Configuration Menu.  
Type the six digit (or less) password, then press Enter. To clear the existing  
password, do not enter numbers for Set Password. Just press enter.  
Figure 10-5  
Loopback Remote 1B  
Figure 10-6  
Set Password Screen  
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Chapter 11  
Troubleshooting  
When the ISU 128 powers up, it performs an internal self test. This takes about  
10 seconds. At the end of the test, the front panel displays Self Test Passed.  
IF SELF TEST FAILS  
If Self Test Passed is not displayed, perform the following procedure to verify  
if the problem can be fixed locally:  
1. Ensure that the ISU 128 is receiving power and is switched on.  
2. Turn off the ISU 128. While holding down the 0 key, power back on. Con-  
tinue to press 0 for 15 seconds. This will reset all the internal settings to  
factory defaults.  
3. If the ISU 128 still does not pass self test, call ADTRAN Technical Support  
for assistance. See the back of this manual for phone numbers.  
IF THE ISU 128 DOES NOT READ READY  
When the ISU 128 has been set up and connected to an ISDN line but the front  
panel does not read Ready after a few minutes, use the following trouble-  
shooting procedure:  
1. Cycle power on the ISU 128, leaving it off for a minimum of two seconds.  
Turn the power on for one minute to ensure the unit does not read Ready.  
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Chapter 11. Troubleshooting  
2. Disconnect the ISU 128 from the ISDN line. From a functioning voice  
phone, call the local directory number(s) provided with your line. Calling  
a good ISDN line with nothing connected usually results in a ring or fast  
busy tone. If someone answers or a not-in-service intercept is received,  
there is probably something wrong with the translation of the ISDN line.  
The phone service provider should be able to help.  
3. If the ISU 128 continues to read Link Down, there is a physical problem  
with the ISDN phone line (more than likely, a problem with the Layer 1  
setup). The problem may be one or more of the following:  
•
•
•
•
•
•
The ISU 128 software setup  
The ISU 128 hardware  
The wiring on your premises  
The telephone service provider's wiring  
The telephone service provider's hardware  
The telephone service provider's software setup  
To isolate the problem, perform the following procedure:  
A. Make sure the ISU 128 is configured for dial line service. Check that  
CONFIG, Netw. options, Dial Line, is selected on the menu.  
B. Try another piece of functioning ISDN equipment with a U-interface  
on the ISDN line.  
C. Talk to your service provider and ensure you have an ISDN Basic  
Rate U-Interface with 2B1Q line coding (wrong options are an S or T  
interface or AMI line coding).  
D. Ensure that your ISDN phone line is connected to the actual telephone  
line (U-interface) provided by your telephone company. Make sure your  
ISDN line is not connected though another piece of equipment such as  
an NT1 in a wiring closet somewhere.  
E. Make sure nothing else is bridged across the ISDN line pair.  
F. With a minimum of extra wiring, try connecting to the ISDN line pair  
at the point where service provider's wiring ends.  
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Chapter 11. Troubleshooting  
G. With the ISU 128 connected to the ISDN line and powered up, talk to  
your service provider's repair group and inform them that your ISDN  
basic rate line has a physical layer 1 problem. Ask them to check the  
ISDN line. Tell them that you have an NT1-like device at the end of the  
ISDN line.  
4. If the ISU 128 continues to read Getting TEI #1, the ISU 128 is physically  
connected to your local telephone service provider but is unable to estab-  
lish logical layer 2. The problem may be one or more of the following:  
•
•
•
The ISU 128 software setup  
The telephone service provider's software setup  
Hardware configuration if the ISDN line is extended from the switch  
To isolate the problem, use the following procedure:  
A. Ensure the ISU 128 is set up for the correct switch protocol by selecting  
CONFIG, Netw. options, Dial Line, Switch protocl.  
B. Ensure the line quality is satisfactory by checking for near- and far-end  
block errors (NEBEs and FEBEs). To do this, select Test, NEBE/FEBE. If  
the counts are non-zero and incrementing, there may be a physical link  
problem as described under Link Down (Step 3).  
C. Try another piece of functioning ISDN equipment with a U-interface  
on the line.  
D. With the ISU 128 connected to the line and powered up, talk to your  
service provider's repair group and tell them you have an ISDN basic  
rate line that appears physically okay but has no terminal endpoint  
identifier (TEI). Ask them to check the ISDN line translation and ensure  
that the ISDN line supports dynamic TEI allocation. Tell them that you  
have an NT1 and terminal adapter device connected to the line.  
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Chapter 11. Troubleshooting  
5. If the ISU 128 continues to read Register SPID #1, the ISU 128 is physically  
connected to the local telephone service provider and has established log-  
ical layer 2. The ISU 128 is unable to establish layer 3. The problem may  
be one or more of the following:  
•
•
The ISU 128 software setup  
The telephone service provider's software setup  
To isolate the problem, use the following procedure:  
A. Ensure the ISU 128 is set up for the correct switch protocol by selecting  
CONFIG, Netw. options, Dial line, Switch protocl.  
B. Ensure the ISDN line is multipoint.  
C. Make sure that the ISU 128 is set up with the correct SPID and LDN by  
selecting CONFIG, Netw. options, Dial Line, Terminal ID, SPID/LDN.  
D. Try another piece of functioning ISDN equipment with a U-interface on  
the line.  
E. With the ISU 128 connected to the ISDN line and powered up, talk to your  
service provider's repair group and tell them you have an ISDN basic rate  
line that appears physically okay but has no terminal endpoint identifier  
(TEI). Ask them to check the line translation and ensure that the line  
supports dynamic TEI allocation. Tell them that you have an NT1 and  
terminal adapter device connected to the line.  
6. If the ISU 128 continues to read Getting TEI #2, the ISU 128 has completely  
initialized the first phone number but is unable to establish logical layer 2  
for the second phone number. The problem may be one or more of the fol-  
lowing:  
•
•
The ISU 128 software setup  
The telephone service provider's software setup  
To isolate the problem, use the following procedure:  
A. Ensure the ISDN line is multipoint with two phone numbers.  
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Chapter 11. Troubleshooting  
B. Ensure that the ISU 128 is set up with the correct SPID and LDN by  
selecting CONFIG, Netw. options, Dial Line, Terminal ID, SPID/LDN.  
C. Try swapping SPID1 with SPID2 and LDN1 with LDN2. Determine if  
the problem is the second phone number or the quantity of phone  
numbers.  
D. Try another piece of functioning ISDN equipment with a U-interface  
on the ISDN line.  
E. With the ISU 128 connected to the ISDN line and powered up, talk to your  
service provider's repair group and tell them you have an ISDN basic rate  
line that appears physically okay but has no TEI. Ask them to check the  
line translation and ensure that the line supports dynamic TEI allocation.  
Tell them that you have an NT1 and terminal adapter device connected  
to the line.  
7. If the ISU 128 continues to read Register SPID #2, the ISU 128 has com-  
pletely initialized the first phone number but is unable to establish logical  
layer 3 for the second phone number. The problem is in one or more of  
the following places:  
•
•
The ISU 128 software setup  
The telephone service provider's software setup  
To isolate the problem, use the following procedure:  
A. Ensure the ISDN line is multipoint with two phone numbers.  
B. Ensure that the ISU 128 is set up with the correct SPID and LDN by  
selecting CONFIG, Netw. options, Dial Line, Terminal ID, SPID/LDN.  
C. Try swapping SPID1 with SPID2 and LDN1 with LDN2.  
Determine if the problem is the second phone number or the quantity  
of phone numbers.  
D. Try another piece of functioning ISDN equipment with a U-interface  
on the line.  
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Chapter 11. Troubleshooting  
E. With the ISU 128 connected to the line and powered up, talk to your  
service provider's repair group and tell them you have an ISDN basic rate  
line that appears physically okay but has no terminal endpoint identifier  
(TEI). Ask them to check the line translation and ensure that the line  
supports dynamic TEI allocation. Tell them that you have an NT1 and  
terminal adapter device connected to the line.  
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Chapter 12  
Specifications  
SPECIFICATIONS AND FEATURES  
This section describes the standard specifications and features incorporated in  
the ISU 128.  
Network Interface  
•
RJ-45 for ISDN Basic Rate U-Interface, and Leased 2B1Q service  
DTE Interface  
•
•
•
RS-530  
V.35  
EIA-232  
Dialing Selections  
•
•
•
•
In-band DTE dialing: V.25 or AT commands  
Manual or automatic stored number dialing, DTR assertion  
Dial interface: RS-366  
Front panel manual dialing  
Data Rates (Network)  
64 kbps (one B channel), 128 kbps (two B channels)  
Data Rates (DTE)  
•
•
300 bps to 115.2 kbps asynchronous  
2400 bps to 128 kbps synchronous  
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Chapter 12. Specifications  
Rate Adaption  
•
•
•
•
•
•
•
•
•
T-Link  
CCITT V.120  
CCITT V.110  
SAP  
DSU 57.6 Async  
BONDING mode 1  
V.34 (optional)  
PPP  
MP  
Interoperability  
•
•
•
•
BONDING Inverse Multiplexers  
Switched 56 DSUs  
ISDN TAs  
V.34 modems (optional)  
Switch Compatibility  
•
•
•
•
AT&T 5ESS  
NTI DMS-100  
National ISDN-1  
NEC  
B Channel Aggregation  
•
•
BONDING Mode 1  
MP  
Display  
•
•
Two-line by 16 character LCD  
LED indicators  
RS  
Request to Send.  
Indicates the DTE is ready to transmit.  
Clear to Send.  
Indicates the ISU 128 is ready to transmit.  
Transmit Data.  
On when the DTE is transmitting to the ISU 128.  
Receive Data.  
On when the ISU 128 is receiving data from the far end.  
Carrier Detect.  
CS  
TD  
RD  
CD  
On when the ISU 128 is connected to a remote unit.  
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Chapter 12. Specifications  
TR  
SR  
Data Terminal Ready from DTE.  
On when DTR is active at DTE interface.  
Data Set Ready.  
Environmental  
•
•
•
Operating Temperature: 0 to 50 °C  
Storage Temperature: 20 to 70 °C  
Relative Humidity: Up to 95%, non-condensing  
Physical  
•
•
Dimensions: 2.25"H x 8.75"W x 11.00"D  
Weight: 3 lbs.  
Power  
•
115 VAC, 60 Hz, 8 W maximum dissipation (part numbers 1202029L2 and  
1202029L3)  
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Chapter 12. Specifications  
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Appendix A  
AT Commands  
This appendix lists the supported AT commands and describes their functions.  
Command  
Function  
A
Answer. Puts the ISU 128 in answer mode.  
Dial. Precedes the telephone access number [ATD5551212].  
Hang up. Disconnects the current call.  
On-line. Commands the unit to go back on line.  
S Register.  
D
H
O
S
SS  
Z
S String register.  
Reset. Resets the AT command processor.  
&N0  
Number 1. Read far-end phone number 1 if service subscribed from  
telephone company.  
&N1  
Number 2. Read far-end phone number 2 if service subscribed from  
telephone company.  
&R  
Ram. Copy EEPROM configuration to RAM.  
Save. Save current configuration to EEPROM.  
&W  
+++  
Break in. Break in AT command processor during an active call. The  
break in key can be defined in S2.  
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Appendix A. AT Commands  
Command  
Function  
Carrier Detect (CD) Control Line Options  
&C0  
&C1  
&C2  
&C3  
CD forced On  
CD normal  
CD off with local disconnect (LOCD)  
CD off with link down  
Data Terminal Ready (DTR Control Line Options)  
&D0  
&D1  
&D2  
Ignore DTR  
DTR off forces command  
Idle when off, DTR off forces idle (On allows auto answer)  
Generic Unit Configurations  
&F0  
&F1  
&F2  
&F3  
&F4  
&F5  
&F6  
&F7  
&F8  
&F9  
&F10  
&F11  
Reset all S-registers to factory preset values  
Configures unit for Dial 56K sync  
Configures unit for Dial 64K sync  
Configures unit for Dial 112K sync  
Configures unit for Dial 128K sync  
Configures unit for Leased 128K  
Configures unit for Ldm 128K master  
Configures unit for Dial 57.6K async  
Configures unit for Dial 115.2K async  
Configures unit for Dial PPP  
Configures unit for Dial V34 115.2 async  
Configures unit for FALLBACK 57.6K async  
Network Options  
&L0  
&L1  
Dial network  
Leased network  
Calling Number Identifiers  
&N0  
&N1  
Number 1. Read far-end phone number 1 if service subscribed from  
telephone company.  
Number 2. Read far-end phone number 2 if service subscribed from  
telephone company.  
DTE Data Type Options  
&Q0  
&Q1  
DTE is async  
DTE is sync  
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Appendix A. AT Commands  
Command  
Function  
Clear-To-Send (CTS) Control Line Options  
&R0  
&R1  
Follows RTS  
Forced CTS  
Data Set Ready (DSR) Control Line Options  
&S0  
&S1  
&S2  
&S3  
DSR forced On  
DSR if call up  
DSR Off if link down  
DSR Off if Dial Up  
DTE Connector Data Synchronous Data Clocking Options  
&X0  
&X1  
Internal transmit clock  
External transmit clock  
Accessing Stored numbers for Dialing Options  
&Z0  
&Z1  
&Z2  
&Z3  
&Z4  
&Z5  
&Z6  
&Z7  
&Z8  
&Z9  
Stored number 0  
Stored number 1  
Stored number 2  
Stored number 3  
Stored number 4  
Stored number 5  
Stored number 6  
Stored number 7  
Stored number 8  
Stored number 9  
Local Echo Options  
E0  
E1  
Echo off. Does not allow command characters typed to be displayed on  
the screen.  
Echo on. Determines if the command characters typed are displayed on  
the screen.  
Unit Identification  
I0  
I1  
Identify unit. Commands the unit to display model number.  
Identify software. Commands the unit to display software version.  
AT Command Response Message Options  
Q0  
Q1  
Response messages on  
Response messages off  
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Appendix A. AT Commands  
Command  
Function  
AT Command Response Message Types  
V0  
V1  
Numeric response messages  
Verbal response messages words  
AT Command Connect Message Options  
X0  
X1-7  
Simple connect message  
Connect messages with bit rate  
Ready-To-Send (RTS) Control Line Options  
_D0  
_D1  
1 ms delay  
18 ms delay  
Service Profile Identification (SPID) Access Options  
_I1  
_I2  
Access SPID 1  
Access SPID 2  
Local Directory Number (LDN) Access Options  
_N0  
_N1  
Access LDN1  
Access LDN2  
ISDN Switch Protocol Options  
_S0  
_S1  
_S2  
_S3  
5ESS  
DMS-100  
National ISDN-1  
NEC  
ISDN U-Interface Operational Mode Options  
_X0  
_X1  
ISU timing slaves to network (NT)  
ISU is U-interface timing master (LT)  
Data Flow Control Options  
\Q0  
\Q1  
\Q2  
\Q3  
\Q4  
No flow control  
Software  
CTS only  
Hardware  
Software from DCE only  
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Appendix A. AT Commands  
Command  
Function  
The following AT commands require that the optional V.34 modem board be installed:  
V.34 Compression Options  
%C0  
%C1  
%C2  
%C3  
No compression  
Use MNP compression  
Use V.42 bis compression  
Use V.42 bis/MNP compression  
V.34 Compression Block Size Options  
\A0  
\A1  
\A2  
\A3  
MNP 64 byte blocks  
MNP 128 byte blocks  
MNP 192 byte blocks  
MNP 256 byte blocks  
V.34 Operational Mode Options  
\N0  
\N1  
\N2  
\N3  
\N4  
\N5  
MNP Normal  
MNP Direct  
Reliable  
Auto-reliable  
Force LAPM  
Force MNP  
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Appendix A. AT Commands  
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Appendix B  
Current Status Messages  
This appendix lists the status line messages and their definitions. Messages  
shown entirely in capital letters are generated by the ISDN network. Messages  
with lower case letters are generated by the ISU 128.  
AT&T-5ESS Ready  
The ISU 128 is connected to an AT&T 5ESS switch and is ready to place/re-  
ceive calls.  
Call Connect B1  
Bearer channel 1 has been connected and is now active.  
Call Connect B2  
Bearer channel 2 has been connected and is now active.  
CALL xxxxxxx  
The ISU 128 is calling phone number xxxxxxx.  
DISCONNECTING  
The current phone call is being disconnected (hung up).  
DMS-100 Ready  
The ISU is connected to a DMS-100 switch and is ready to place/receive calls.  
Getting TEI #1  
The ISU is receiving its first TEI from the network.  
Getting TEI #2  
The ISU is receiving its second TEI from the network.  
ISDN-1 Ready  
The ISU 128 is connected to an ISDN-1 compliant switch and is ready to place/  
receive calls.  
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Appendix B. Current Status Messages  
Link down  
The network interface is not active.  
LPBK DTE Port  
The DTE connector is looped back in the DTE direction.  
LPBK Protcl Net  
The ISU 128 has been commanded to perform a loopback in the network direc-  
tion after letting the incoming data pass through the current protocol.  
NEC Ready  
The ISU 128 is connected to an NEC switch and is ready to place/receive calls.  
NET EOC LOOPBACK  
The ISU 128 has been commanded to perform an ISDN loopback toward the  
network.  
NET REM LOOPBACK  
The ISU 128 is performing a V.54 or DDS latching loopback toward the net-  
work.  
Register SPID #1  
The ISU 128 is registering its first SPID with the network.  
Register SPID #2  
The ISU 128 is registering its second SPID with the network.  
RINGING  
The phone number just dialed is ringing.  
xxxx nnnn  
A rate adaption is running at the bit rate specified by nnnn.  
xxxxx Quitting  
A rate adaption protocol is turning off.  
xxxxx Ready  
A rate adaption protocol is ready.  
xxxxx Setup  
A rate adaption protocol is setting up.  
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Appendix B. Current Status Messages  
xxxxx can be any of the following:  
BONDING  
Bandwidth on Demand Industry Users Group protocol.  
CLEAR CHAN  
No rate adaption protocol (allows use of maximum bandwidth).  
DSTOP  
DSU 57.6 async rate adaption protocol.  
FALLBACK  
FALLBACK rate adaption protocol.  
PPP  
Point-to-point protocol.  
SAP  
Simple ADTRAN protocol.  
TLINK  
TLINK rate adaption protocol.  
V110  
V.110 rate adaption protocol.  
V120  
V.120 rate adaption protocol.  
V34  
V.34 modem (optional).  
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Appendix B. Current Status Messages  
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Appendix C  
Status Buffer Messages  
This appendix lists the status buffer message and their definitions. Messages  
shown entirely in capital letters are generated by the ISDN network. Messages  
with lower case letters are generated by the ISU 128.  
Answer 1/2  
The ISU 128 answered a call on either the first or second channel. The calling  
phone number is displayed if available.  
ACCESS_INFO_DISCARDED  
The network was unable to deliver access information to the far end.  
Back to on-line  
ISU 128 went back on line.  
Bad async BPS  
The BONDING protocol determined that the selected asynchronous bit rate is  
not supported.  
Bad AT bit field  
User issued an AT command with an argument that was out of range.  
Bad B channel  
Bonding negotiation determined the delay in one of the Bearer channels was  
uncorrectable.  
Bad call type  
ISU 128 placed a call with an improper call type.  
Bad DTE baud  
The DTE bit rate does not match a valid bit rate for the protocol selected.  
Bad DTE bps  
Bonding negotiation determined the chosen DTE bit rate is invalid.  
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Appendix C. Status Buffer Messages  
BAD_INFO_ELEM  
Call control error.  
Bad phone number  
ISU 128 attempted to call an invalid phone number.  
Bad TLK Version  
Invalid TLINK parameters found during end-to-end negotiations.  
BaudRate  
ISU 128 does not support the negotiated TLINK baud rate.  
BEAR_CAP_NOT_AVAIL  
The bearer channel requested by the user is not available.  
Bearer mode  
Incoming call is not of a type the ISU128 can accept.  
Bearer info mode  
Incoming call information transfer capability is not known.  
BONDING (+/- XXX)  
The amount of bytes of corrected delay between the B2 and B1 bearer channels  
(XXX can range from -8000 to +8128 bytes).  
BPS mismatch  
Bonding negotiation found a bit rate mismatch.  
Break to AT cmd  
User issued a break-in request (+++).  
Break ignored  
User issued an extra break-in request.  
BUSY  
The called number is busy.  
CallID 1 in use  
ISU 128 tried to place a call using SPID 1 though SPID 1 was already in use.  
CallID 2 in use  
ISU 128 tried to place a call using SPID 2 though SPID 2 was already in use.  
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Appendix C. Status Buffer Messages  
Call not ringing  
User executed an answer command (ATA) but there was not a call present.  
CALL_REJECTED  
The call has been rejected by the ISDN Network.  
Can’t go on-line  
ISU 128 cannot go back on line. User issued an unknown AT command.  
CAP_NOT_IMPLEMENTED  
The network or far end does not support the bearer capability requested.  
CHAN_DOES_NOT_EXIST  
The bearer channel requested is not present.  
CHAN_NOT_IMPLEMENTED  
The bearer channel requested has not been implemented.  
CHANNEL_UNACCEPTABLE  
The channel requested has not been subscribed.  
CID>0 rcvd  
Received an incoming call from a third party during negotiations with a far-  
end BONDING unit on the use of the second bearer channel.  
DEST NOT ISDN  
The number called is not ISDN (warning only).  
DEST_OUT_OF_ORDER  
The called number is out of order.  
Dial 1/2  
The ISU 128 placed a call on either the first or second channel. The number  
called is displayed following the message.  
Disconnect 1/2  
The call on either the first or second channel was disconnected from the net-  
work. The far-end phone number is displayed if available.  
Disconnect Req  
Far-end unit disconnected during BONDING negotiation.  
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Appendix C. Status Buffer Messages  
DPUMP END RCVD  
Indication of a hang-up or disconnect occurring during BONDING. Does not  
indicate an error condition has occurred.  
DTE must be SYNC  
For the protocol chosen, the DTE connector must be optioned as synchronous.  
DTE not set V25  
The DTE equipment is not optioned for the same bit rate as the ISU 128 for V.25  
bis dialing.  
DTR not up  
ISU 128 tried to place a call in a dialing mode that requires DTR to be in an ac-  
tive state but it is not.  
Dump call  
ISU 128s could not accept an incoming call because it was already involved in  
a call.  
Dump 1/2  
An incoming call on either the first or second channel was discarded by the  
ISU. The calling number is displayed if available.  
FACILITY_NOT_IMPLEMENT  
The network does not support the requested supplementary service.  
FACILITY_REJECTED  
A facility requested cannot be provided by the network.  
FACILITY_NOT_SUBSCRIBED  
The channel type requested has not been subscribed.  
FALLBACK ERROR  
Attempted to fallback to normal mode failed.  
FBW disconnect  
BONDING negotiation has failed due to a disconnect on a B-Channel.  
FlowCtl mismatch  
Bonding negotiation determined a flow control mismatch.  
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Appendix C. Status Buffer Messages  
FlowCtl required  
Bonding negotiation determined that flow control needs to be optioned on.  
Hangup 1/2  
The call on either the first or second channel was disconnected by the ISU 128.  
The far-end phone number is also displayed.  
InCmptblFound  
TLINK end-to-end negotiations found an optioning incompatibility between  
the two end units.  
INCOMMING_CALL_BARRED  
The network will not allow an incoming call.  
INCOMPATIBLE_DEST  
The called number cannot accept the type of call that has been placed.  
INVALID_CALL_REF  
Call control error.  
INVALID_ELEM_CONTENTS  
Call control error.  
INVALID_MSG_UNSPEC  
Invalid message, protocol error.  
INVALID_NUMBER_FORMAT  
The dialed number has an invalid format.  
L1 not up  
The network interface is not active.  
L2 not up  
The data link layer interface is not active.  
L3 not up  
The call control interface is not active.  
L2 #2 not up  
The data link layer interface for a second call (BONDING) is not active.  
L3 #2 not up  
The call control layer interface for a second call (BONDING ) is not active.  
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Appendix C. Status Buffer Messages  
LDN TOO LONG  
The entered local directory number has too many digits.  
MANDATORY_IE_LEN_ERR  
Mandatory information element length error.  
MANDATORY_IE_MISSING  
Mandatory information element missing.  
Need 2 B chan  
The DTE bit rate requires the BONDING protocol.  
Need 64K call  
The BONDING protocol requires the ISU 128 to be configured for a 64k data  
call type.  
Negotiation fail  
The BONDING negotiation has failed.  
NETWORK BUSY  
The ISDN switch is busy and unable to process a call.  
NETWORK_CONGESTION  
The phone network is currently congested.  
NETWORK_OUT_OF_ORDER  
The phone network is out of order.  
No 48K Support  
The ISU 128 does not support 48 kbps TLINK. Local DTE setup error.  
NO_CIRCUIT_AVAILABLE  
The requested bearer channel is not available.  
NO_CARRIER  
The V.34 modem board did not detect a modem carrier at the far end.  
NONEXISTENT_MSG  
Nonexistent message was sent by the ISU 128.  
No Sreg number  
Attempt to access an S-register without specifying a specific S-register (exam-  
ple: ATS=1).  
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Appendix C. Status Buffer Messages  
No Sreg value  
Attempt to change an S-register without specifying a value  
(example: ATS2= ).  
NO_ROUTE  
The phone network was unable to find a route to the destination number.  
NO_USER_RESPONDING  
The dialed number is not responding.  
NORMAL_CLEARING  
The network is disconnecting the current call.  
NOT end2end ISDN  
The path that the call was routed over is not ISDN from end-to-end (warning  
only).  
NUMBER_CHANGED  
The number dialed has been changed.  
OUTGOING_CALL_BARRED  
The network will not allow the outgoing call to be placed.  
PROTOCOL_ERROR  
Call control error.  
REQ_CHANNEL_NOT_AVAIL  
The channel type requested is currently not available.  
Remote not ISU  
Bonding negotiation determined the far-end unit is not another ISU product  
(asynchronous rates can only be supported between two ADTRAN ISU prod-  
ucts).  
RESP_TO_STAT_ENQ  
Response to status enquiry.  
Ring 1/2  
An incoming call on either the first or second channel (third channel if call  
waiting) entered the Ring state. The calling phone number is displayed if  
available.  
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Appendix C. Status Buffer Messages  
S cmd not = or ?  
User did not use proper syntax.  
SAP idle timeout  
Unit at far end is not configured to use the SAP protocol.  
SERVICE_NOT_AVAIL  
The service requested by the user is not available.  
SOURCE NOT ISDN  
The incoming calling party is not ISDN (warning only).  
SReg SetError  
Local DTE invalid S-register setting.  
Sync BPS < 56K  
The synchronous bit rate selected is too slow for the BONDING protocol.  
Sync Mismatch  
Both ends Bad Synchronization.  
TAINIT expired  
Bonding timer TAINIT expired.  
TANULL expired  
Bonding timer TANULL expired, non-BONDING equipment attempted to  
call into the ISU 128 while optioned for BONDING.  
TEMPORARY_FAILURE  
The network has temporarily failed, try the call again.  
TIMER_EXPIRY  
Call control error.  
TLINK ErrorOne  
Catastrophic TLINK error.  
TXADD01 expired  
Bonding timer TXADD01 expired, probably making a long distance call to a  
foreign country, adjust timer value to correct.  
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Appendix C. Status Buffer Messages  
TXFA1 expired  
Bonding timer TXFA1 expired, other vendors BONDING equipment did not  
operate properly.  
TXFA2 expired  
Bonding timer TXFA1 expired, other vendors BONDING equipment did not  
operate properly.  
TX FLOW ERROR  
Flow control needs to be enabled.  
TXINIT expired  
Bonding timer TXINIT expired, called non-BONDING equipment.  
UNASSIGNED_NUMBER  
The phone number dialed does not exist.  
Unknown AT & cmd  
User issued an unknown AT command.  
UNSPECIFIED_CAUSE  
Received a cause message from the network that is not understood.  
Unsupported baud  
The ISU 128 does not support the negotiated baud rate.  
USER_BUSY  
The dialed number is busy.  
V120 timeout  
The far-end unit is not set up for V.120.  
V120 connected  
The V.120 rate adaption successfully connected to the far-end unit.  
WRONG_MESSAGE  
Call control error.  
WRONG_MSG_FOR_STATE  
Call control error.  
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Appendix C. Status Buffer Messages  
106  
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Appendix D  
S-Register List  
S0  
S2  
AUTO ANSWER  
Determines how the ISU 128 answers an  
incoming call.  
0
1
2
= Disable (ISU 128 does not answer call).  
= Enable (ISU 128 answers all calls).  
= Dump all calls.  
BREAK IN  
CHARACTER  
Determines which key or character (in ASCII code)  
defines the escape command. The standard escape  
character is a + sign (ASCII value of 43 decimal). To  
change the character set, set S2 to the desired ASCII value.  
Range = 0 to 127  
S3  
S4  
END OF LINE  
CHARACTER  
Determines which key or character (in ASCII code)  
ends a command line. The standard end-of-line  
character is the carriage return (ASCII value of  
13 decimal).  
Range = 0 to 127  
LINE FEED  
CHARACTER  
Determines which key or character (in ASCII code)  
advances the cursor to the next line after ending a  
command line or after an ISU 128 message. The  
standard character is the line feed (ASCII value of  
10 decimal).  
Range = 0 to 127  
S5  
S7  
BACK SPACE  
CHARACTER  
Determines which key moves the cursor back one  
space to erase a character. The standard character is  
the backspace (ASCII value of 8 decimal).  
Range = 0 to 127  
CONNECT TIME  
Determines how long the ISU 128 waits for an  
outgoing call to be answered.  
15 = 15 seconds  
30 = 30 seconds  
60 = 1 minute  
120 = 2 minutes  
240 = 4 minutes  
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Appendix D. S-Register List  
S11 FALLBACK DEFAULT Determines how the ISU 128 answers an  
incoming call if all of the protocols in Fallback failed.  
1 = Clear Channel  
2 = BONDING Mode 1  
3 = SAP  
4 = T-link  
5 = V.110  
6 = V.120  
7 = V.34  
8 = DSU 57.6 Async (default)  
9 = PPP asyn-syn  
S12 ESCAPE TIME  
S14 MISC BITS  
Determines the delay required immediately before  
and after entering the escape command for the ISU 128  
to recognize and execute the command.  
Range = 0 to 127  
Miscellaneous bits (bit 8 is most significant bit).  
Bit 2 = 1: Enables on-screen echo of AT commands.  
Bit 2 = 0: Disables on-screen echo of AT commands.  
Bit 3 = 0: Enables AT responses from the ISU 128.  
Bit 3 = 1: Disables AT responses from the ISU 128.  
Bit 4 = 1: Enables AT responses to be displayed in  
text form.  
Bit 4 = 0: Enables AT responses to be displayed in  
numeric form.  
Bit 7 = 1: Disables PPP ACCM Spoofing.  
Bit 7 = 0: Enables PPP ACCM Spoofing.  
Bit 8 = 1: Ring indicator uses cadence.  
Bit 8 = 0: Ring indicator remains on.  
S15 ASYNC BONDING  
S22 MSG BITS  
0 = ADTRAN Only  
1 = Multi-Vendor  
Miscellaneous message bits (Bit 8 is most significant  
bit).  
Bit 5 = Bit 6 = Bit 7 = 1 : Allows connect message  
with baud rate.  
Bit 5 = Bit 6 = Bit 7 = 0 : Connects message without  
baud rate.  
S24 V120 LLC  
Value determines whether the V.120 bit is set in setup  
message for CCITT V.120 calls. Some terminal adapters  
require this bit be set to connect V.120 calls.  
0 = Set V.120 bit in call setup message. (default)  
1 = Do not set V.120 bit in call setup message.  
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Appendix D. S-Register List  
S27 PPP MODE  
S30 DTE CTS  
Determines type of PPP connection.  
0= Single-link operation (default)  
1= Multilink operation  
2= Use compression  
Controls the operation of the DTE connector clear to send  
(CTS) line.  
0= Follows RTS  
1= Force CTS  
S31 DTE RTS  
S32 DTE DSR  
Controls operation of the request to send (RTS) line.  
0= 1 ms delay  
17= 18 ms delay  
Controls the operation of the data set ready (DSR) signal on  
the DTE connectors.  
0= Force DSR on always  
1= DSR off OOS + Test  
2= DSR off Link Down  
S33 DTE CD  
Controls the operation of the carrier detect (CD) line on the  
DTE connectors.  
0= Force CD on always  
1= CD is active during a call (normal operation)  
2= Off with LOCD  
S34 DTE DTR  
S35 DTE CONN  
Determines how the ISU 128 responds to changes in DTR.  
This is a bit-mapped register.  
0= Ignore DTR.  
1= Force AT command mode when DTR is off  
2= Dump incoming call when DTR is off  
Determines which is the current operating DTE connector.  
0= RS-530 connector  
1= V.35  
2= EIA-232 connector  
S-registers 36 through 38 require the optional V.34 modem P/N 1202029L3.  
61202.029L2-1  
ISU 128 User Manual  
109  
 
Appendix D. S-Register List  
S36 ERROR  
Sets the type of error control to be negotiated with  
the far-end modem.  
CORRECTION  
0 = Normal operation no error control. Allows speed  
matching, buffering, and flow control.  
1 = Direct error control, no error control. Does not allow  
the terminal and ISU 128 to operate at different  
speeds or use flow control.  
2 = Reliable MNP error control. If the far end does  
not use MNP error control then the call is ended.  
3 = Auto-reliable MNP error control . The ISU 128  
attempts to use MNP error control. If the far end  
does not use MNP, then normal operation is used.  
4 = Force LAPM. Force the modem to connect only  
if V.42 (LAPM) error correct can be used.  
5 = Force MNP. Force the modem to connect only if  
MNP 2-4 error correction can be used.  
S37 V34  
Enables compression in the V.34 modem.  
0 = No compression  
COMPRESSION  
1 = MNP5 compression  
2 = V42 compression  
3 = MNPS or V42 compression  
S38 V34 BLOCK SIZE  
Sets the amount of data sent in a single packet during  
MNP error controlled stream operation.  
0 = Block size of 64 bytes  
1 = Block size of 128 bytes  
2 = Block size of 192 bytes  
3 = Block size of 256 bytes  
S40 BOND TXINIT  
S41 BOND TXFA  
Specifies the number of seconds the originating endpoint  
attempts to detect the BONDING negotiation pattern  
from the answering endpoint before deciding the  
BONDING call has failed.  
Range = 0 to 255, 10 sec is default  
Specifies the number of seconds both endpoints attempt  
to detect the BONDING frame pattern when a call is  
connected before deciding the BONDING call has failed.  
When operating with other manufacturers' BONDING  
equipment, it may be necessary to lengthen this timer so  
that it matches TXADD01.  
Range = 0 to 255, 10 sec is default  
110  
ISU 128 User Manual  
61202.029L2-1  
 
Appendix D. S-Register List  
S42 BOND TXADD01  
The number of seconds both endpoints wait for the  
additional call to be connected at the end of negotiation  
before deciding the BONDING call has failed. When  
dialing overseas, it may be necessary to lengthen this  
timer to allow for lower call routing.  
Range = 0 to 255, 50 sec is default  
S43 BOND TXDEQ  
S44 BOND TANULL  
The number of seconds both endpoints attempt to  
equalize the network delay between the bearer channels  
before deciding the BONDING call has failed.  
Range = 0 to 255, 50 sec is default  
The number of seconds the answering endpoint attempts  
to detect the BONDING negotiation pattern from the  
originating endpoint before aborting to clear channel  
mode. It may be necessary to shorten this timer if the  
DTE equipment connected to the ISU 128 also has  
timer constraints for completing non-BONDING para-  
meter negotiation.  
Range = 0 to 255, 10 sec is default  
S45 BOND TCID  
S46 V25 MODE  
S47 RS-366 TIME  
The number of seconds both endpoints attempt to  
negotiate agreeable values for bearer channels and  
channel capacities before deciding the BONDING  
call has failed.  
Range = 0 to 255, 5 sec is default  
Selects the type of V.25 bis dialing used.  
0 = Asynchronous V.25  
1 = HDLC V.25  
2 = BISYNC V.25  
3 = HDLC with flags V.25  
Determines the amount of time the RS-366 port will wait  
for EON or inactivity to terminate a dial string before  
dialing a number.  
0 = Wait for EON only  
10= Wait for 1 second or EON  
20= Wait for 2 seconds or EON  
50= Wait for 5 seconds or EON  
100=Wait for 10 seconds or EON  
200=Wait for 20 seconds or EON  
S50 LINE MODE  
Selects the operating mode of the ISU 128.  
0 = Dial service (switched service)  
1 = Leased service (non-switched service)  
61202.029L2-1  
ISU 128 User Manual  
111  
 
Appendix D. S-Register List  
S51 LINE CLOCK  
Selects the clock mode in leased mode.  
0 = Slave (default)  
1 = Master (Leased line only, limited distance  
MODEM application only).  
S52 SWITCH  
PROTOCOL  
Selects the network switch type for dial service.  
0 = AT&T 5ESS  
1 = Northern Telecom DMS-100  
2 = National ISDN-1  
3 = NEC  
S53 CALL TYPE  
Call type (dial service only)  
0 = Speech  
1 = Audio  
2 = 56 kbps data  
3 = 64 kbps data  
S54 PROTOCOL  
TYPE  
Rate adaption protocol type.  
1 = Clear Channel (no rate adaption)  
2 = BONDING mode 1  
3 = SAP (simple ADTRAN protocol)  
4 = T-link  
5 = V.110  
6 = V.120  
7 = V.34  
9 = DSU 57.6 kbps asynchronous  
11= FALLBACK  
12= PPP async-to-sync  
S55 DIAL MODE  
S56 ECHO TONE  
Selects dialing interface.  
0 = Front panel only (always available)  
1 = RS-366 dialing port  
2 = AT commands  
3 = V.25 bis dialing  
Enables an echo tone which suppresses the echo  
cancellers in a voice circuit. Can be used to trick the  
switch to allow sending data over a line optioned for  
voice ISDN service.  
0 = None  
1 = Answer  
2 = Originate  
3 = Both  
112  
ISU 128 User Manual  
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Appendix D. S-Register List  
S57 DDS TEST  
Allows an ISU 128 optioned as a leased line unit to  
respond to DDS in-band latching loopback or V.54  
loopback commands.  
0 = No checking  
1 = Check for DDS latching loopbacks  
2 = Check for v.54 loopbacks  
3 = Check for V.54 and DDS latching loopbacks  
S58 CALL SCREENING Allows the ISU 128 to screen incoming calls.  
0 = Answer any call  
1 = Answer only calls from numbers matching  
those stored in SN0 through SN9.  
S59 CHANNEL RATE  
Sets the available network bandwidth when the ISU  
128 is in leased mode.  
3 = 64 kbps  
5 = 128 kbps  
SS60 SPID1 LOC  
SS61 SPID2 LOC  
SS62 LDN1 LOC  
SS63 LDN2 LOC  
Primary SPID location.  
Secondary SPID string location.  
Primary local directory number string location.  
Secondary local directory number string location.  
S70  
DTE MODE  
Selects asynchronous or synchronous mode on the DTE  
connector.  
0 = Asynchronous  
1 = Synchronous  
S71  
DTE RATE  
Selects the DTE connector bit rate.  
1 = 300  
3 = 1200  
6 = 2400  
8 = 4800  
11= 9600  
15= 19200  
17= 38400  
18= 48000  
19= 56000  
20= 57600  
21= 64000  
22= 112020  
23= 115200  
24= 128000  
61202.029L2-1  
ISU 128 User Manual  
113  
 
Appendix D. S-Register List  
S72  
S73  
DATA BITS  
DTE PARITY  
Selects the number of asynchronous data bits.  
0 = 8 bits  
1 = 7 bits  
Selects the number of asynchronous parity bits.  
0 = None  
1 = Odd  
2 = Even  
S74  
S75  
DTE STOP  
DTE FLOW  
Selects the number of asynchronous stop bits.  
0 = 1 stop bit  
1 = 1.5 stop bits  
2 = 2 stops bits  
Selects asynchronous flow control.  
0 = None  
1 = Hardware flow XON/OFF from DCE controls DTE  
2 = XON/OFF from DTE controls DCE  
3 = Hardware flow. RTS and CTS flow control.  
12= Software flow. XON/OFF controls DTE and DCE.  
S76  
DTE CLOCK  
Selects DTE connector transmit clock timing source.  
0 = Internal (ISU 128 supplies timing)  
1 = External (DTE supplies timing)  
The following are the string locations for stored numbers 0 - 9.  
SS80 SN0 LOC  
SS81 SN1 LOC  
SS82 SN2 LOC  
SS83 SN3 LOC  
SS84 SN4 LOC  
SS85 SN5 LOC  
SS86 SN6 LOC  
SS87 SN7 LOC  
SS88 SN8 LOC  
SS89 SN9 LOC  
Stored number 0 string  
Stored number 1 string  
Stored number 2 string  
Stored number 3 string  
Stored number 4 string  
Stored number 5 string  
Stored number 6 string  
Stored number 7 string  
Stored number 8 string  
Stored number 9 string  
114  
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61202.029L2-1  
 
Appendix E  
Connector Pinouts  
PIN 13  
PIN 25  
PIN 1  
FEMALE  
PIN 14  
Figure E-1  
EIA-232/RS-530 Interface  
Table E-A  
EIA-232 Interface  
Pin  
Name  
Shield  
TD  
I/O  
I/O  
I
O
I
O
O
I/O  
O
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
O
Description  
1
2
3
4
5
6
7
8
Shield for cable  
Transmitted Data  
Received Data  
Request to Send  
Clear To Send  
Data Set Ready  
Signal Ground  
Carrier Detect  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
Transmit Clock  
No Connection  
Receive Clock  
RD  
RTS  
CTS  
DSR  
SG  
CD  
NC  
NC  
NC  
NC  
NC  
NC  
TC  
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
NC  
RC  
N/A  
O
NC  
NC  
DTR  
NC  
RI  
NC  
ETC  
NC  
N/A  
N/A  
I
N/A  
O
N/A  
I
N/A  
No Connection  
No Connection  
Data Terminal Ready  
No Connection  
Ring Indicator  
No Connection  
External Transmit Clock  
No Connection  
I= Input, O= Output, N/A= Not Applicable  
61202.029L2-1  
ISU 128 User Manual  
115  
 
Appendix E: Connector Pinouts  
Table E-B  
RS-530 Interface  
Pin  
Name  
Shield  
I/O  
Description  
1
I/O  
Shield for cable  
2
3
4
5
6
7
TD-A  
RD-A  
RTS-A  
CTS-A  
DSR-A  
SG  
I
Transmitted Data  
Received Data  
Request to Send  
Clear To Send  
Data Set Ready  
Signal Ground  
O
I
O
O
I/O  
8
9
CD-A  
RC-B  
CD-B  
ETC-B  
TC-B  
CTS-B  
TD-B  
TC-A  
RD-B  
RC-A  
NC  
RTS-B  
DTR-A  
NC  
DSR-B  
DTR-B  
ETC-A  
NC  
O
O
O
I
O
O
I
O
O
O
N/A  
I
I
Carrier Detect  
Receive Clock (return)  
Carrier Detect (return)  
External Transmit Clock (return)  
Transmit Clock (return)  
Clear To Send (return)  
Transmit Data (return)  
Transmit Clock  
Receive Data (return)  
Receive Clock  
No Connection  
Request To Send (return)  
Data Terminal Ready  
No Connection  
Data Set Ready (return)  
Data Terminal Ready (return)  
External Transmit Clock  
No Connection  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
N/A  
O
I
I
N/A  
I= Input, O= Output, N/A= Not Applicable  
116  
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61202.029L2-1  
 
Appendix E: Connector Pinouts  
V .35  
B
A
R
V
Z
Y
DD  
JJ  
F
E
L
NN  
LL  
J
N
T
X
D
C
BB FF  
K
P
U
CC HH MM  
EE KK  
AA  
M
S
W
H
Figure E-2  
V.35 Interface  
Table E-C  
V.35 Interface  
Pin  
Name  
Shield  
SG  
I/O  
Description  
A
B
C
D
E
I/O  
I/O  
I
O
O
Shield for cable  
Signal Ground  
Request To Send  
Clear To Send  
Data Set Ready  
Carrier Detect  
RTS  
CTS  
DSR  
CD  
F
O
H
J*  
P
R
S
T
U
V
W
X
Y
AA  
K,L  
M,N  
BB  
CC  
DD  
EE  
FF  
HH  
JJ  
KK  
LL  
MM  
NN  
DTR  
RI  
I
Data Terminal Ready  
Ring Indicator  
Send Data  
O
I
O
I
O
I
O
I
SD-A  
RD-A  
SD-B  
RD-B  
TC-A  
RC-A  
TC-B  
RC-B  
ST-A  
ST-B  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
Receive Data  
Send Data (return)  
Receive Data (return)  
External Transmit Clock  
Receive Clock  
External Transmit Clock (return)  
Receive Clock (return)  
Send Timing  
Send Timing (return)  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
No Connection  
O
O
O
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
*Pin J (ring indicator) is needed for most video conferencing applications.  
I= Input, O= Output, N/A= Not Applicable  
61202.029L2-1  
ISU 128 User Manual  
117  
 
Appendix E: Connector Pinouts  
PIN 13  
PIN 25  
PIN 1  
FEMALE  
PIN 14  
Figure E-3  
RS-366 Interface  
Table E-D  
RS-366 Interface  
Pin  
Name  
I/O  
Description  
Shield for cable  
Digit Present  
1
2
Shield  
DPR  
I/O  
I
3
4
5
6
ACR  
CRQ  
PND  
PWI  
SG  
DSC  
NB1  
NB2  
NB4  
NB8  
DLO  
NC  
O
I
O
O
I/O  
O
I
I
Abandon Call and Retry  
Call Request  
Present Next Digit  
Power Indication  
Signal Ground  
Distant Station Connect  
Digit LSB  
Digit bit 2  
Digit bit 3  
Digit bit MSB  
Data Line Occupied  
No Connection  
No Connection  
No Connection  
7
13  
14  
15  
16  
17  
22  
8-12  
18-21  
23-25  
I
I
O
N/A  
N/A  
N/A  
NC  
NC  
I= Input, O= Output, N/A= Not Applicable  
PIN 1 PIN 8  
ISDN  
Figure E-4  
RJ-45 Interface  
Table E-E  
RJ-45 ISDN IFC  
Pin  
Description  
4
5
Ring  
Tip  
118  
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61202.029L2-1  
 
Appendix E: Connector Pinouts  
PIN 13  
PIN 25  
PIN 1  
FEMALE  
PIN 14  
Figure E-5  
Maintenance Port  
Table E-F  
Maintenance Port  
Pin  
Name  
I/O  
Description  
2
3
TD-A  
RD-A  
I
Transmitted Data  
Received Data  
O
61202.029L2-1  
ISU 128 User Manual  
119  
 
Appendix E: Connector Pinouts  
120  
ISU 128 User Manual  
61202.029L2-1  
 
Acronyms  
AMI  
Alternate Mark Inversion  
ANSI  
American National Standards Institute  
A 64 kbps digital information channel  
Bandwidth On Demand Interoperability Group  
Bits per second  
B (Channel)  
BONDING  
bps  
BRI  
Basic Rate Interface  
CCITT  
Consultative Committee for International Telegraphy and  
Telephony  
CD  
Carrier Detect  
CIC  
Carrier Identification Code  
Customer Premises Equipment  
Central Processing Unit  
Call Request (using stored number)  
Call Request (number in command)  
Clear to Send  
Data Communications Equipment  
Disconnect Incoming Call  
Digital Multiplex Switching  
Directory Number  
CPE  
CPU  
CRS  
CRN  
CTS  
DCE  
DIC  
DMS  
DN  
DSR  
DTE  
EIA  
EKTS  
ESS  
FAX  
FEBE  
ID  
Data Set Ready  
Data Terminal Equipment  
Electronic Industries Association  
Electronic Key Telephone Service  
Electronic Switching System  
Facsimile  
Far End Block Errors  
Identification  
I/O  
Input/Output  
ISDN  
kbps  
kHz  
LAN  
Integrated Services Digital Network  
Kilobits per second  
Kilohertz  
Local Area Network  
61202.029L2-1  
ISU 128 User Manual  
121  
 
Acronyms  
LATA  
Mbps  
MF  
MNP  
NEBE  
NT  
Local Access and Transport Area  
Megabits per second  
Multi-Frequency Signalling  
Microcom™ Network Protocol  
Near End Block Errors  
Network Termination  
PBX  
PC  
Private Branch Exchange  
Personal Computer  
POTS  
PRI  
Plain Old Telephone Service  
Primary Rate Interface  
PRN  
RAM  
RLN  
RTS  
SPCS  
SAP  
SPID  
SS7  
Program Stored Number  
Random Access Memory  
List Stored Number  
Ready to Send  
Stored Program Controlled Switching System  
Simple Adtran Protocol  
Service Profile Identifier  
Signalling System 7  
TA  
Terminal Adapter  
TE  
Terminal Equipment  
TEI  
USART  
Terminal Endpoint Identifier  
Universal Synchronous/Asynchronous Receiver/  
Transmitter  
WAN  
Wide Area Network  
122  
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61202.029L2-1  
 
Glossary  
B-Channel  
64 kbps bearer channel used for voice, circuit, or packet switched data.  
bearer service  
As defined by CCITT standards, a type of telecommunication service that provides the  
capability for the transmission of information between user-to-network interfaces.  
Bearer services defined for ISDN are circuit mode and packet mode.  
BONDING mode 1 Protocol  
Industry standard B channel aggregation protocol. Developed by the Bandwidth on  
Demand Interoperability Group.  
CCITT  
Consultative Committee on International Telephony and Telegraphy. A body of the  
International Telegraph Union (ITU) which prepares recommendations, commonly  
referred to as international standards, to resolve technical telegraph and telephone  
problems.  
central office (CO)  
In telephony, the phone company switching facility or center, usually a Class 5 end  
office, at which subscribers local loops terminate. Handles a specific geographic area,  
identified by the first three digits of the local telephone number. Usually the facilities  
of the local BOC.  
clear channel  
A channel in which all the 64 kbps are used for transmission. To achieve this bit  
robbing signalling must be eliminated.  
D-channel  
The ISDN channel that carrier signalling information to control the call setup,  
teardown, or invocation of supplementary services. The D-Channel may also be used  
to provide packet mode data service.  
61202.029L2-1  
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123  
 
Glossary  
DDS  
Dataphone Digital Service. AT&T private line service for transmitting data over a  
digital system. The digital transmission system transmits electrical signals directly,  
instead of translating the signals into tone of varied frequencies as with traditional  
analog transmission systems. Digital techniques provide more efficient use of  
transmission facilities, resulting in lower error rates and costs than analog systems.  
digital loopback  
Technique for testing the digital processing circuitry of a communications device. May  
be initiated locally or remotely via a telecommunications circuit. Device being tested  
will echo back a received test message after first decoding and then encoding it.  
The results are compared with the original message (compare with analog loopback).  
four-wire circuits  
Telephone lines using two wires for transmitting and two wires for receiving offering  
much higher quality than a 2-wire circuit. All long distance circuits are 4-wire. Almost  
all local phone lines and analog phones are 2-wire.  
hub  
(1) Communications center, (2) Major routing station for connecting channels, (3) DDS  
connecting center.  
in-band signalling  
Signalling made up of tones which pass within the voice frequency band and are  
carried along the same circuit as the talk path being established by the signals.  
Virtually all signalling (request for service, dialing, disconnect, etc.) in the U.S. is  
in-band signalling. Most of that signalling is MF (multi-frequency) dialing. The more  
modern form of signalling is out-of-band.  
interexchange carrier  
Since divestiture, any carrier registered with the FCC authorized to carry customer  
transmissions between LATAs interstate, or if approved by a state public utility  
commission, intrastate. Includes carriers such as AT&T Communications, Satellite  
Business Systems, GTE Telenet, GTE Sprint, and MCI.  
information element  
The name for the data fields within an ISDN Layer 3 message.  
interworking  
Communication between two types of networks or end equipment. This may or may  
not involve a difference in signalling or protocol elements supported.  
124  
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61202.029L2-1  
 
Glossary  
ISDN  
Integrated Services Digital Network. A network architecture that enables end-to-end  
digital connections. The network supports diverse services through integrated access  
arrangements and defines a limited set of standard, multipurpose interfaces for  
equipment vendors, network providers, and customers. Interworking with a public  
switched telephone network is retained.  
LATA  
Local Access and Transport Area. One of 161 local telephone serving areas in the  
United States, generally encompassing the largest standard statistical metropolitan  
areas. Subdivisions established as a result of the AT&T divestiture that now  
distinguish local from long distance service. Circuits with both end-points within  
the LATA (intraLATA) are generally the sole responsibility of the local telephone  
company, while circuits that cross outside the LATA (interLATA) are passed on to an  
interexchange carrier.  
loopback  
A diagnostic procedure where data is sent to the device being tested, and the output of  
the device is fed directly back to its input, looped around, and the returning data is  
checked against that which was sent.  
message  
The Layer 3 information that is passed between the CPE and SPCS for signalling.  
multiplexing  
The combining of multiple data channels onto a single transmission medium. Any  
process through which a circuit normally dedicated to single user can be shared by  
multiple users. Typically, user data streams are interleaved on a bit or byte basis  
(time division) or separated by different carrier frequencies (frequency division).  
multipoint circuit  
A circuit consisting of three or more stations connected directly electrically.  
narrowband ISDN  
A collective term for BRA and PRA at speeds up to 1.544 Mbps.  
non-ISDN line  
Any connection from a CPE to a SPCS that is not served by D-Channel signalling.  
non-ISDN trunk  
Any trunk not served by either SS7 or D-Channel signalling.  
NT1  
Network Termination 1. A unit that provides physical and electromagnetic  
termination of the U-interface 2-wire transmission line, converts between Layer 1  
formats used at the U- and T- reference points, and performs some maintenance  
functions.  
61202.029L2-1  
ISU 128 User Manual  
125  
 
Glossary  
NT2  
Network Termination 2. A unit that provides switching and concentration of  
subscriber lines at the S-interface. This unit performs the functions of a customer  
premises switch or multiplexer to multiplex B-channel(s) and D-channel(s) onto one  
physical path and to route calls to the appropriate B or D channel.  
PRA  
Primary Rate Access. Connects high-capacity CPE, such as PBXs, to the network.  
In the US, this is composed of twenty-three 64 kbps channels and one 64 kbps  
D-channel. Also known as Primary Rate Interface (PRI).  
point-to-point  
Describing a circuit connecting two points directly with no intermediate processing  
nodes or computers (although switching facilities could exist). A type of connection  
that links two logical entities (i.e., phone-line circuit).  
serving area  
Region surrounding a broadcasting station where signal strength is at or above a stated  
minimum. The geographic area handled by a telephone central office facility.  
Generally equivalent to a LATA.  
S-interface  
S-Reference point. The interface that connects an ISDN terminal (TE1) or Terminal  
Adapter (TA) to the NT2 reference point as defined in the I.411 Recommendation.  
SPCS  
Stored Program Controlled Switch. A digital switch that supports call control, routing,  
and supplementary services provision under software control. All ISDN switches are  
SPCSs.  
synchronous  
(1) The condition occurring when two events happen in a specific time relationship  
with each other, both under control of a master clock; (2) A method of data  
transmission requiring the transmission of timing pulses to keep the sender and  
receiver synchronized in their communication used to send blocks of information.  
Synchronous data transmission is used in high speed data circuits because there is less  
overhead than asynchronous transmission of characters which contain two extra bits  
per character to effect timing.  
T1  
Also T-1. A digital transmission link with a capacity of 1.544 Mbps. T1 uses two pairs  
of normal twisted wires. T1 normally can handle 24 voice conversations with each  
conversation being digitized at 64 kbps. With more advanced digital voice encoding  
techniques, it can handle more voice channels. T1 is a standard for digital transmission  
in North America.  
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Glossary  
T1C  
3.152 Mbps. Capable of handling 48 voice conversations. T1C is further up the North  
American digital carrier hierarchy.  
T2  
6.312 Mbps. Capable of handling 96 voice conversations. T2 is four times the capacity  
of T1.  
T3  
44.736 Mbps. Commonly referred to as 45 Mbps. Capable of handling 672 voice  
conversations. T3 runs on fiber optic and is typically called FT3.  
TA  
Terminal Adaptor. A DCE that connects to the ISDN S-Interface and enables  
non-ISDN terminal equipment to communicate over the ISDN.  
TE1  
Terminal Equipment Type 1. ISDN-compatible terminals.  
TE2  
Terminal Equipment Type 2. Non-ISDN terminal equipment linked at the EIS-232,  
RS-449, or V.35 interfaces.  
tandem  
The connection of networks or circuits in series. The connection of the output of one  
circuit to the input of another.  
T-interface  
T-Reference point. Performs the same function as the S-Interface but uses an NT1,  
rather than an NT2.  
twisted pair  
Two wires twisted around each other to reduce induction (interference) from one wire  
to the other. Several sets of twisted pair wires may be enclosed in a single cable.  
Twisted pair is the normal cabling from a central office to your home or office, or from  
your PBX to your office phone. Twisted pair wiring comes in various thicknesses.  
As a general rule, the thicker the cable is, the better the quality of the conversation and  
the longer cable can be and still get acceptable conversation quality. However, the  
thicker it is, the more it costs.  
61202.029L2-1  
ISU 128 User Manual  
127  
 
Glossary  
2B+D  
The Basic Rate Interface (BRI) in ISDN. A single ISDN circuit divided into two 64 kbps  
digital channels for voice or data and one 16 kbps channel for low speed data (up to  
9,600 baud) and signalling. 2B+D is carried on one or two pairs of wires depending  
on the interface, the same wire pairs that today bring a single voice circuit int  
o your home or office. See ISDN.  
23B+D  
In ISDN, also known as the Primary Rate Interface. A circuit with a wide range of  
frequencies that is divided in twenty-three 64 kbps paths for carrying voice, data,  
video, or other information simultaneously. It bears a remarkable similarity to today's  
T1 link, except that T1 carries 24 voice channels. In ISDN, 23B+D gives twenty-three  
channels and one D channel for out of band signalling. However, in T1, signalling is  
handled in band. See ISDN.  
two-wire circuit  
A transmission circuit composed of two wires, signal and ground, used to both send  
and receive information. In contrast, a 4-wire circuit consists of two pairs. One pair  
is used to send. One pair is used to receive. All trunk circuits (long distance) are  
4-wire. A 4-wire circuit delivers better reception, but also costs more. All local loop  
circuits (those coming from a Class 5 central office to the subscriber's phone system)  
are 2-wire, unless a 4-wire circuit is requested.  
U-interface  
A twisted pair subscriber loop that connects the NT1 reference point to the ISDN  
network, as defined in the I.411 Recommendation. This interface provides Basic Rate  
Access with an operating frequency of 160 kbps and an information rate of 144 kbps.  
Under U.S. regulations, this also marks the line of demarcation between customer-  
owned equipment and the public network.  
video-conferencing  
The real-time, usually two-way, transmission of digitized video images between tw  
o or more locations. Teleconferencing requires a wideband transmission facility.  
Transmitted images may be freeze-frame (where television screen is repainted every  
few seconds to every 20 seconds) or full motion. Bandwidth requirements for two-way  
video conferencing range from 6 MHz for analog, full-motion, full-color, commercial  
grade TV to 56 kbps for digitally-encoded freeze-frame to 1.544 kbps for very good  
quality, full-color, full-motion TV.  
wideband  
Generally, a communications channel offering a transmission bandwidth greater than  
a voice grade channel. Data transmission speeds on wideband facilities are typically  
in excess of 9.6 kbps and often at rates such as 56 kbps and 1.544 Mbps.  
128  
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61202.029L2-1  
 
Glossary  
X.25  
A packet data transfer protocol for the B and D Channels. Defines the interface  
between Data Terminal Equipment (DTE) and Data Circuit Terminating Equipment  
(DCE) for terminals operating in the packet mode and connected to public data  
networks by dedicated circuits.  
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ISU 128 User Manual  
129  
 
Glossary  
130  
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61202.029L2-1  
 
Index  
A
C
answer call 68  
cable lengths 12  
call screening 38  
call type 24  
answer tone 37  
always tone 37  
incoming tone 37  
audio 25  
no answer tone 37  
outgoing tone 37  
data 56 kbps 25  
data 64 kbps 25  
default 25  
asynchronous data format 45  
AT command  
speech 24, 25  
connect message options 90  
remote configuration 71  
response message options 89  
response message types 90  
AT commands 30, 87  
changing S-register strings 32  
changing S-registers 32  
dialing a call using the AT command  
processor 32  
calling number identifiers 88  
Capability B 10  
Capability C 10  
Capability R 9, 10  
Capability S 10  
carrier detect 88  
CD options 43  
channel rate 41  
clear channel 7, 48  
reading S-register strings 32  
reading s-registers 32  
using AT commands 31  
using S-registers 31  
audio 25  
clear to send control line options 89  
clock mode  
master 40  
slave 40  
compression 52, 57  
configuration 23  
quick setup 59  
auto answer  
disabled 36  
dump all calls 36  
remote 71  
enabled 36  
configuration menu 18  
configure remote unit 73  
VT 100 screen 73  
connect timeout 38  
connector pinouts 115  
EIA-232 interface 115  
B
B-channel aggregation 84  
bit rate 42  
BONDING mode 1 7, 26, 48  
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ISU 128 User Manual  
131  
 
Index  
maintenance port 119  
dial options 29  
AT commands 30  
RJ-45 ISDN IFC 118  
RS-366 interface 118  
RS-530 116  
disabled 35  
front panel 29  
RS-366 29  
V.35 interface 117  
connector type 43  
connector types  
EIA-232 12  
V.25 bis 33  
dial ppp 62  
dial stored number 68  
RS-366 12  
dialing  
RS-530 12  
ways to dial 2  
V.35 12  
dialing options 67  
answer call 68  
CTS options 43  
current status messages 93  
dial number 68  
dial stored number 68  
hang up line 68  
D
redial last number 68  
store/review number 69  
dialing selections 83  
display 84  
data 56 kbps 25  
data 64 kbps 25  
data bits 34  
data flow control options 90  
DSR options 44  
data format  
DSU 57.6 async 53  
asynchronous flow control) 44  
transmit clock 45  
data format (asynchronous) 45  
data rates 83  
DTE  
data rates 83  
interface 83  
DTE connector data synchronous data  
clocking options 89  
DTE control line options 88  
DTE data connection 12  
DTE data rates 83  
DTE date type options 88  
DTE indicators 3  
DTE interface 83  
cable lengths 12  
DTE options 42  
data set ready control line options 89  
dial 112k sync 61  
dial 115.2 asyn 64  
dial 128k sync 62  
dial 56K 7  
dial 56k sync 60  
dial 56K*2 7  
dial 57.6 asyn 63  
dial 64K 7  
dial 64k sync 61  
dial 64K*2 7  
bit rate 42  
CD options 43  
connector type 43  
CTS options 43  
data format (async) 45  
DSR options 44  
DTR options 43  
dial interface connection 12  
dial line  
menu tree 23  
operation 23  
dial number 68  
132  
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Index  
flow control (async data format ) 44  
RTS options 43  
interoperability 84  
ISDN  
basic rate service 11  
basic rate service (defined) 2  
ordering codes 9  
Capability B 10  
transmit clock (sync) 45  
DTR options 43  
dump all calls 36  
Capability C 10  
Capability R 9, 10  
Capability S 10  
E
EIA-232 12  
interface 115  
Generic Data I 9  
overview 1  
environmental specifications 85  
EON (end of number) 30  
error control 51  
switch protocol options 90  
U-interface operational mode op-  
tions 90  
ISU 128  
F
front panel 3  
factory setup 66  
fallback 54  
57.6k 64  
FAX service 12  
features 83  
interoperability 4  
overview 1  
rear panel 2  
specifications and features 83  
L
flow control 6, 7  
flow control (async data format) 44  
front panel 29  
ldm 128 master 65  
LDN  
function keys 15  
setting 26  
LDN access options 90  
leased 128K 7, 65  
leased 64K 7  
G
Generic Data I 9  
generic unit configurations 88  
getting started 16  
leased line 40  
channel rate 41  
clock mode 40  
leased line service  
defined 2  
H
LED indicators 84  
local echo options 89  
loopback disable 21  
DDS accepted 21  
DDS+V54 accept 22  
no remote loopbacks 21  
V.54 accepted 21  
hang up line 68  
I
if self test fails 77  
if the ISU 128 does not read ready 77  
installation 11  
61202.029L2-1  
ISU 128 User Manual  
133  
 
Index  
loopback DTE 20  
point-to-point protocol 56  
power supply 85  
PPP  
with compression 57  
ppp 7  
loopback network 20  
loopback points 20  
loopback protocol 20  
loopback remote 21  
loopback remote 1B 74  
VT 100 screen 75  
ppp async-to-sync 56  
protocol options 47  
BONDING mode 1 7, 48  
clear channel 7, 48  
DSU 57.6 async 53  
fallback 54  
loopback remote 2B 74  
M
maintenance interface 13, 119  
menu navigation 15  
menu tree  
multilink ppp 56  
ppp 7, 56  
ppp async-sync 56  
SAP 7, 53  
main branches 16  
microcom™ network protocol block size  
(MNP® blk) 52  
T-link 7, 53  
V.110 7, 51  
more 65  
multilink ppp 56  
V.120 7, 50  
V.34 51  
protocols  
N
rate adaption 54  
recommended 6, 7  
NEBE/FEBE 22  
negotiation fail 102  
network  
Q
data rates 83  
quick setup 59  
interface 83  
dial 112k sync 61  
dial 115.2 asyn 64  
dial 128k sync 62  
dial 56k sync 60  
dial 57.6 asyn 63  
dial 64k sync 61  
dial ppp 62  
options 88  
network connection 11  
O
operating protocols  
recommended 6, 7  
operation 15  
factory setup 66  
fallback 57.6k 64  
ldm 128 master 65  
leased 128K 65  
V34 115.2 async 63  
ordering ISDN with IOCs 9  
P
password  
remote configuration 74  
physical specifications 85  
134  
ISU 128 User Manual  
61202.029L2-1  
 
Index  
R
SPID access options 90  
S-registers 107  
rate adaption 84  
rate adaption protocols 54  
recommended operating protocols 6, 7  
redial last number 68  
remote configuration 71, 73  
AT commands 71  
loopback remote 1B 74  
loopback remote 2B 74  
menu path 72  
status buffer 16  
messages 97  
status menu 17  
store/review number 69  
stored numbers 89  
switch compatibility 84  
switch protocol 24  
synchronous data format  
transmit clock 45  
set password 74  
testing 72  
T
VT 100 screen 72  
remote testing 74  
repair and return 11  
RJ-45  
TANULL 50  
TCID 50  
terminal identification 25  
test menu 19  
connector 11  
test menu path 74  
test menu tree 20  
test options 19  
loopback disable 21  
loopback DTE 20  
loopback network 20  
loopback protocol 20  
loopback remote 21  
NEBE/FEBE 22  
software version 22  
test remote 21  
test remote 21  
testing 19  
interface 118  
jack 2  
RS-366 12, 29  
interface 118  
menu tree 29  
RS-530 12  
interface 116  
RTS control line options 90  
RTS options 43  
S
SAP 7  
self test failure 77  
set password 74  
VT 100 screen 75  
Simple ADTRAN Protocol (SAP) 53  
software version 22  
specifications 83  
speech 24  
time-out 29  
timers 49, 50  
T-link 7, 53  
troubleshooting 77  
TXADD01 50  
TXDEQ 50  
TXFA 49  
SPID  
TXINIT 49  
obtaining 25  
setting 25  
61202.029L2-1  
ISU 128 User Manual  
135  
 
Index  
U
unit identification 89  
V
V.110 7, 51  
V.120 7, 50  
V.25  
V.25 HDLC flag 35  
V.25 sync bisync dialing 35  
V.25 sync HDLC dialing 35  
V.25 bis 33  
menu tree 33  
V.25 async dialing 34  
V.34 51  
compression block size options 91  
compression options 91  
operational mode options 91  
V.35 12  
interface 117  
V34 115.2 async 63  
videoconferencing 12  
VT 100  
configuration screen 18  
set password screen 75  
VT 100 terminal  
configuration screen 18, 24  
dial options screen 67  
status screen 17  
test screen 19  
136  
ISU 128 User Manual  
61202.029L2-1  
 
Product Support Information  
Presales Inquiries and Applications Support  
Please contact your local distributor, ADTRAN Applications Engineering, or  
ADTRAN Sales:  
Applications Engineering  
Sales  
(800) 615-1176  
(800) 827-0807  
Post-Sale Support  
Please contact your local distributor first. If your local distributor cannot help,  
please contact ADTRAN Technical Support and have the unit serial number  
available.  
Technical Support  
(888) 4ADTRAN  
Repair and Return  
If ADTRAN Technical Support determines that a repair is needed, Technical  
Support will coordinate with the Return Material Authorization (RMA) de-  
partment to issue an RMA number. For information regarding equipment  
currently in house or possible fees associated with repair, contact RMA direct-  
ly at the following number:  
RMA Department  
(205) 963-8722  
Identify the RMA number clearly on the package (below address), and return  
to the following address:  
ADTRAN, Inc.  
RMA Department  
901 Explorer Boulevard  
Huntsville, Alabama 35806  
RMA # _____________  
 

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