61202.011L1 1B DSU III AR User Manual

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User Manual: DSU III AR User Manual

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DSU III AR
Data Service Unit

User Manual
Part Number
1202011L1

61202011L1-1C
May 2001

Trademark Information
Open View is a registered trademark of Hewlett-Packard Company.
SunNet Manager is a registered trademark of Sun Microsystems, Inc.
Netview is a registered trademark of IBM.
IQ View is a trademark of ADTRAN, Inc.
Hayes is a trademark of Hayes Microcomputer Products, Inc.
This product includes software developed by the University of California, Berkeley,
and its contributors.

901 Explorer Boulevard
P.O. Box 140000
Huntsville, AL 35814-4000
(256) 963-8000
© 2001 ADTRAN, Inc.
All Rights Reserved.
Printed in U.S.A.

The following conventions are used in this manual.
m

Notes provide additional useful information.

Cautions signify information that could prevent service interruption.

Warnings provide information that could prevent damage to the equipment or endangerment to human life.

iii

FCC regulations require that the following information be provided in this manual:
1. This equipment complies with Part 68 of the FCC rules. On the bottom of the
equipment housing is a label that shows the FCC registration number and Ringer
Equivalence Number (REN) for this equipment, if applicable. If required, this
information must be given to the telephone company.
2. The following information may be required when applying to the local telephone
company for leased line facilities.
Service
Type
2.4 kbps Digital Interface
4.8 kbps Digital Interface
9.6 kbps Digital Interface
19.2 kbps Digital Interface
38.4 kbps Digital Interface
56 kbps Digital Interface
64 kbps Digital Interface

7.
8.

Digital Facility
Interface Code

Service Order
Code

Network
Jacks

04DU5-24
04DU5-48
04DU5-96
04DU5-19
04DU5-38
04DU5-56
04DU5-64

6.0F
6.0F
6.0F
6.0F
6.0F
6.0F
6.0F

RJ-48S
RJ-48S
RJ-48S
RJ-48S
RJ-48S
RJ-48S
RJ-48S

An FCC compliant telephone cord with a modular plug may be provided with
this equipment. This equipment is designed to be connected to the telephone network or premises wiring using a compatible modular jack, which is FCC Part 68
compliant. See installation instructions for details.
If this equipment causes harm to the telephone network, the telephone company
may temporarily discontinue service. If possible, advance notification is given;
otherwise, notification is given as soon as possible. The telephone company will
advise the customer of the right to file a complaint with the FCC.
The telephone company may make changes in its facilities, equipment, operations,
or procedures that could affect the proper operation of this equipment. If this happens, the telephone company will provide advance notification and the opportunity
to make the necessary modifications to maintain uninterrupted service.
If experiencing difficulty with this equipment, please contact ADTRAN for repair and
warranty information. If the equipment is causing harm to the network, the telephone
company may request this equipment to be disconnected from the network until the
problem is resolved or it is certain that the equipment is not malfunctioning.
This unit contains no user serviceable parts.
The FCC recommends that the AC outlet to which equipment requiring AC
power is to be installed is provided with an AC surge arrester.

Federal Communications Commission Radio Frequency Interference Statement
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in
a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio frequencies. Operation of this equipment
in a residential area is likely to cause harmful interference in which case the user will
be required to correct the interference at his own expense.
Shielded cables must be used with this unit to ensure compliance with Class A FCC
limits.
Change or modifications to this unit not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

Affidavit Requirements for Connection to Digital Services
•

An affidavit is required to be given to the telephone company whenever digital
terminal equipment without encoded analog content and billing protection is
used to transmit digital signals containing encoded analog content which are
intended for eventual conversion into voice band analog signal and transmitted
on the network.

•

The affidavit shall affirm that either no encoded analog content or billing information is being transmitted or that the output of the device meets Part 68 encoded
analog content or billing protection specification.

•

End use/customer will be responsible to file an affidavit with the local exchange
carrier when connecting unprotected CPE to a 1.544 Mbps or subrate digital service.

•

Until such time as subrate digital terminal equipment is registered for voice applications, the affidavit requirements for subrate services are waived.

CANADIAN EQUIPMENT LIMITATIONS
Notice: The Canadian Industry and Science Canada label identifies certified equipment. 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, users should ensure that it is permissible to be connected to the facilities of the local telecommunications company. The equipment must
also be installed using an acceptable methods 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). The customer
should be aware that compliance with the above limitations may not prevent degradation of service in some situations.
Repairs to certified equipment should be made by an authorized Canadian maintenance facility designated by the supplier. Any repairs or alterations made by the user
to this equipment, or equipment malfunctions, may give the telecommunications
company 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 contract 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.

CANADIAN EMISSIONS REQUIREMENTS
This digital apparatus does not exceed the Class A 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 A prescrites dans la norme sur le materiel brouilleur:
"Appareils Numeriques," NMB-003 edictee par le ministre des Communications.

IMPORTANT SAFETY INFORMATION
When using your telephone equipment, please follow these basic safety precautions
to reduce the risk of fire, electrical shock, or personal injury:
1.

Do not use this product near water, such as near a bath tub, wash bowl, kitchen
sink, laundry tub, in a wet basement, or near a swimming pool.

Avoid using a telephone (other than a cordless-type) during an electrical storm.
There is a remote risk of shock from lightning.

Do not use the telephone to report a gas leak in the vicinity of the leak.

Use only the power cord, power supply, and/or batteries indicated in the manual.
Do not dispose of batteries in a fire. They may explode. Check with local codes
for special disposal instructions.

SAVE THESE INSTRUCTIONS

vii

Affidavit for Connection of Customer Premises Equipment to 1.544 MBPS and/
or Subrate Digital Services
For the work to be performed in the certified territory of ______________ (telco name)
State of ________________________________
County of ______________________________
I, _______________________ (name), ____________________ (business address),
_____________________ (telephone number) being duly sworn, state:
I have the responsibility for the operation and maintenance of the terminal equipment
to be connected to 1.544 Mbps and/or __________________ subrate digital services.
The terminal equipment to be connected complies with Part 68 of the FCC rules
except for the encoded analog content and billing protection specification. With
respect to encoded analog content and billing protection:
( ) I attest that all operations associated with the establishment, maintenance and adjustment of the digital CPE with respect to encoded analog content and billing protection
information continuously complies with Part 68 of the FCC rules and Regulations.
( ) The digital CPE does not transmit digital signals containing encoded analog content or billing information which is intended to be decoded within the telecommunications network.
( ) The encoded analog content and billing protection is factory set and is not under
the control of the customer.
I attest that the operator(s) maintainer(s) of the digital CPE responsible for the establishment, maintenance and adjustment of the encoded analog content and billing
information has (have) been trained to perform these functions by successfully having
completed one of the following (check appropriate blocks):
( ) A. A training course provided by the manufacturer/grantee of the equipment used
to encode analog signals; or
( ) B. A training course provided by the customer or authorized representative, using
training materials and instructions provided by the manufacturer/grantee of the
equipment used to encode analog signals; or

viii

( ) C. An independent training course (e.g., trade school or technical institution) recognized by the manufacturer/grantee of the equipment used to encode analog signals; or
( ) D. In lieu of the proceeding training requirements, the operator(s)/maintainer(S) is
(are) under the control of a supervisor trained in accordance with _______________
(circle one) above.
I agree to provide ____________________ (telco’s name) with proper documentation
to demonstrate compliance with the information in the preceding paragraph, if so
requested.
_____________________ Signature
_____________________ Title
_____________________ Date
Subscribed and sworn to before me
This _________ day of ___________________, 20__
_______________________________________
Notary Public
My commission expires: _________________________

LIMITED PRODUCT WARRANTY
ADTRAN warrants that for five (5) years from the date of shipment to Customer, all
products manufactured by ADTRAN will be free from defects in materials and
workmanship. ADTRAN also warrants that products will conform to the applicable
specifications and drawings for such products, as contained in the Product Manual or
in ADTRAN's internal specifications and drawings for such products (which may or
may not be reflected in the Product Manual). This warranty only applies if Customer
gives ADTRAN written notice of defects during the warranty period. Upon such
notice, ADTRAN will, at its option, either repair or replace the defective item. If
ADTRAN is unable, in a reasonable time, to repair or replace any equipment to a
condition as warranted, Customer is entitled to a full refund of the purchase price
upon return of the equipment to ADTRAN. This warranty applies only to the original
purchaser and is not transferable without ADTRAN's express written permission.
This warranty becomes null and void if Customer modifies or alters the equipment in
any way, other than as specifically authorized by ADTRAN.
EXCEPT FOR THE LIMITED WARRANTY DESCRIBED ABOVE, THE FOREGOING
CONSTITUTES THE SOLE AND EXCLUSIVE REMEDY OF THE CUSTOMER AND
THE EXCLUSIVE LIABILITY OF ADTRAN AND IS IN LIEU OF ANY AND ALL
OTHER WARRANTIES (EXPRESSED OR IMPLIED). ADTRAN SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, INCLUDING (WITHOUT LIMITATION),
ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. SOME STATES DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, SO THIS EXCLUSION MAY NOT APPLY TO CUSTOMER.
In no event will ADTRAN or its suppliers be liable to Customer for any incidental,
special, punitive, exemplary or consequential damages experienced by either Customer or a third party (including, but not limited to, loss of data or information, loss
of profits, or loss of use). ADTRAN is not liable for damages for any cause whatsoever
(whether based in contract, tort, or otherwise) in excess of the amount paid for the
item. Some states do not allow the limitation or exclusion of liability for incidental or
consequential damages, so the above limitation or exclusion may not apply to Customer.

Customer Service, Product Support Information, and Training
ADTRAN will replace or repair this product within five years from the date of shipment if the product does not meet its published specification, or if it fails while in service.
A return material authorization (RMA) is required prior to returning equipment to
ADTRAN. For service, RMA requests, training, or more information, see the toll-free
contact numbers given below.
Presales Inquiries and Applications Support
Please contact your local distributor, ADTRAN Applications Engineering, or
ADTRAN Sales:
Applications Engineering (800) 615-1176
Sales

(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

The Custom Extended Services (ACES) program offers multiple types and levels of service plans which allow you to choose the kind of assistance you need. For questions,
call the ACES Help Desk.
ACES Help Desk

(888) 874-2237

Repair and Return
If ADTRAN Technical Support determines that a repair is needed, Technical Support
will coordinate with the Custom and Product Service (CAPS) department to issue an
RMA number. For information regarding equipment currently in house or possible
fees associated with repair, contact CAPS directly at the following number:
CAPS Department

(256) 963-8722

Identify the RMA number clearly on the package (below address), and return to the following address:
ADTRAN Customer and Product Service
901 Explorer Blvd.
Huntsville, Alabama 35806

RMA # _____________
Training
The Enterprise Network (EN) Technical Training Department offers training on our
most popular products. These courses include overviews on product features and functions while covering applications of ADTRAN's product lines. ADTRAN provides a variety of training options, including customized training and courses taught at our
facilities or at your site. For more information about training, please contact your Territory Manager or the Enterprise Training Coordinator.

xii

Training - phone

(800) 615-1176, ext. 7500

Training - fax

(256) 963 7941

Training - email

training@adtran.com

Table of Contents
List of Figures ..................................................................................................................... xix
List of Tables ....................................................................................................................... xxi
Chapter 1. Introduction
Product Overview ............................................................................................................... 1-1
DDS Overview............................................................................................................... 1-2
4-Wire Switched 56 Overview..................................................................................... 1-2
Chapter 2. Installation
Unpack, Inspect, Power Up ............................................................................................... 2-1
ADTRAN Shipments Include...................................................................................... 2-1
Customer Provides ....................................................................................................... 2-1
Power Up........................................................................................................................ 2-2
Rear Panel ............................................................................................................................. 2-3
Network Interface Connection.................................................................................... 2-4
DTE Data Connection/Primary DTE......................................................................... 2-4
Secondary Channel Connection.................................................................................. 2-4
Chapter 3. Operation
Front Panel Menu Structure .............................................................................................. 3-1
Main Menu.................................................................................................................... 3-1
Status ...................................................................................................................... 3-2
Test .......................................................................................................................... 3-2
Configuration (Config) ......................................................................................... 3-2
Dial .......................................................................................................................... 3-2
Basic Menu Travel......................................................................................................... 3-3
Enter ................................................................................................................. 3-3
Up Arrow ........................................................................................................ 3-3
Down Arrow .................................................................................................. 3-3

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Table of Contents

Cancel .............................................................................................................. 3-3
Front Panel ........................................................................................................................... 3-5
LCD Window ................................................................................................. 3-5
Enter ................................................................................................................. 3-5
Numeric Keypad ............................................................................................ 3-5
Up and Down Arrows ................................................................................... 3-5
Cancel .............................................................................................................. 3-5
Shift .................................................................................................................. 3-6
Quick ................................................................................................................ 3-6
LED Descriptions .......................................................................................................... 3-6
Chapter 4. Configuration Overview
Local And Remote Configuration .................................................................................... 4-1
Configuration Methods ................................................................................................ 4-2
VT-100 Connection........................................................................................................ 4-5
AT Commands............................................................................................................... 4-6
V.25 Bis Commands ...................................................................................................... 4-7
SDLC Option ......................................................................................................... 4-7
Character Format ........................................................................................... 4-7
Command Structure ...................................................................................... 4-7
Bi-Sync Option ....................................................................................................... 4-7
Character Format ........................................................................................... 4-7
Command Structure ...................................................................................... 4-7
Asynchronous Option .......................................................................................... 4-8
Character Format ........................................................................................... 4-8
Command Structure ...................................................................................... 4-8
Command Descriptions ................................................................................ 4-8
Syntax and Possible Responses ........................................................................... 4-9
CIC (Connect Incoming Call) ....................................................................... 4-9
CNL (Configuration Local) ........................................................................ 4-10
CNR (Configuration Remote) .................................................................... 4-10
Switched 56 Operation ....................................................................................... 4-10
CRN (Call Request with Number) ............................................................ 4-10
CRS (Call Request Using Stored Number) ............................................... 4-11
DIC(Disregard Incoming Call) ................................................................... 4-11
PRN (Program Number) ............................................................................. 4-11
RLN (Request List of Numbers) ................................................................ 4-12
Chapter 5. Network Configuration
Network Options ................................................................................................................. 5-1
Loop Rate........................................................................................................................ 5-1

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Table of Contents

Network Address.......................................................................................................... 5-3
Remote Configuration .................................................................................................. 5-4
Network Type................................................................................................................ 5-5
Clock Source .................................................................................................................. 5-6
Chapter 6. Configuring DTE Options
DTE Options ........................................................................................................................ 6-1
DTE Rate......................................................................................................................... 6-2
Connector Type ............................................................................................................. 6-5
Data Format ................................................................................................................... 6-6
DTE Command Option ................................................................................................ 6-7
Transmit Clock .............................................................................................................. 6-8
CS Options ................................................................................................................... 6-10
Anti-Stream.................................................................................................................. 6-12
Carrier Detect (CD) Options...................................................................................... 6-13
TR Options ................................................................................................................... 6-14
SR Options ................................................................................................................... 6-15
Auxiliary Port .............................................................................................................. 6-16
Chapter 7. Configuring Test Options
Test Options ......................................................................................................................... 7-1
Test Time-out................................................................................................................. 7-1
Remote Digital Loopback ............................................................................................ 7-2
EIA Local Loopback...................................................................................................... 7-3
EIA Remote Loopback.................................................................................................. 7-4
Chapter 8. Configuring Dial Options
Dial Options ......................................................................................................................... 8-1
Phone Number .............................................................................................................. 8-1
Auto Answer.................................................................................................................. 8-2
Chapter 9. Manual Command
Manual Command .............................................................................................................. 9-1
Using the Front Panel to Enter a Manual Command .............................................. 9-2
Chapter 10. Dial Selection
dial Options ........................................................................................................................ 10-1
Dial Stored Number.................................................................................................... 10-2
Enter Dial Number...................................................................................................... 10-2
Redial Last Number.................................................................................................... 10-2

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Table of Contents

Chapter 11. Testing and Troubleshooting
TEST OVERVIEW .............................................................................................................. 11-1
Initiating a Test ............................................................................................................ 11-2
Test Status Display...................................................................................................... 11-3
Exiting a Test................................................................................................................ 11-3
Troubleshooting ................................................................................................................. 11-5
Messages from the DSU/CSU................................................................................... 11-5
Troubleshooting New Installs ................................................................................... 11-6
Test Sequence for Troubleshooting New Installs or Existing Circuits ........ 11-8
Local Unit diagnostics .................................................................................................... 11-10
DTE and Loop (LL) ................................................................................................... 11-12
Test Description ................................................................................................. 11-12
Test Purpose ....................................................................................................... 11-12
Initiating ............................................................................................................. 11-13
Interpreting Test Results .................................................................................. 11-13
Loop Only (RT).......................................................................................................... 11-14
Test Purpose ....................................................................................................... 11-14
Initiating ............................................................................................................. 11-15
Interpreting Test Results .................................................................................. 11-15
DTE Only.................................................................................................................... 11-16
Test Purpose ....................................................................................................... 11-16
Initiating ............................................................................................................. 11-17
Interpreting Test Results .................................................................................. 11-17
DTE With Test Pattern.............................................................................................. 11-18
Test Purpose ....................................................................................................... 11-18
Initiating ............................................................................................................. 11-19
Interpreting Test Results .................................................................................. 11-19
Test Pattern ................................................................................................................ 11-20
Test Purpose ....................................................................................................... 11-20
Initiating ............................................................................................................. 11-21
Interpreting Test Results .................................................................................. 11-21
Self Test....................................................................................................................... 11-22
Test Purpose ....................................................................................................... 11-22
Initiating ............................................................................................................. 11-22
Interpreting Test Results .................................................................................. 11-22
Remote Unit Diagnostics ................................................................................................ 11-23
Test Purpose ....................................................................................................... 11-24
Initiating ............................................................................................................. 11-24
Test Results ........................................................................................................ 11-24
Interpreting Test Results .................................................................................. 11-25

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Table of Contents

Chapter 12. Viewing Status Information
STATUS display ................................................................................................................ 12-1
DSU Operational Status ............................................................................................. 12-2
DDS Network Status................................................................................................... 12-3
Network Rate............................................................................................................... 12-4
DTE Rate/Mode.......................................................................................................... 12-4
DTE Control Leads and Status.................................................................................. 12-4
Appendix A. Pinouts ....................................................................................................... A-1
Appendix B. AT Commands ........................................................................................... B-1
Appendix C. Default Configuration Profiles ............................................................. C-1
Appendix D. EIA-232 Connector................................................................................... D-1
Appendix E. DSU to DSU Tail Circuit.......................................................................... E-1
Appendix F. Specifications Summary........................................................................... F-1
Appendix G. Acronyms/Abbreviations ....................................................................... G-1
Appendix H. Glossary ..................................................................................................... H-1
Index ............................................................................................................................Index-1

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Table of Contents

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List of Figures
Figure 1-1. Sample Point-to-Point Application for DSU III AR................................... 1-2
Figure 2-1. DSU III AR Rear View .................................................................................... 2-3
Figure 3-1. Main Menu LCD Display .............................................................................. 3-1
Figure 3-2. Example of Basic Menu Travel...................................................................... 3-4
Figure 3-3. DSU III AR Front View .................................................................................. 3-5
Figure 4-1. Complete Configuration Menu .................................................................... 4-3
Figure 4-2. Configuration Menu with DTE Options ..................................................... 4-4
Figure 5-1. Setting Loop Rate Options ............................................................................ 5-2
Figure 5-2. Setting the Network Address........................................................................ 5-3
Figure 5-3. Enabling/Disabling Remote Configuration ............................................... 5-4
Figure 5-4. Setting Network Type Options ..................................................................... 5-5
Figure 5-5. Setting the Clock Source ................................................................................ 5-6
Figure 6-1. DTE Rates for 56 or 64 kbps Loop Rate with No Secondary Channel.... 6-2
Figure 6-2. DTE Rates for 56 kbps Secondary Channel and 64 kbps Loop Rates ..... 6-3
Figure 6-3. Selecting the Connector Type........................................................................ 6-5
Figure 6-4. Selecting Asynchronous or Synchronous Data Format ............................ 6-6
Figure 6-5. Selecting DTE Command Option................................................................. 6-7
Figure 6-6. Transmit Clock Options ................................................................................. 6-8
Figure 6-7. Selecting CS Options .................................................................................... 6-10
Figure 6-8. Anti-Stream Options .................................................................................... 6-12
Figure 6-9. Selecting CD Options ................................................................................... 6-13
Figure 6-10. Selecting TR Options.................................................................................... 6-14
Figure 6-11. Setting SR Options........................................................................................ 6-15
Figure 6-12. Setting the Secondary Rate.......................................................................... 6-16
Figure 7-1. Setting Test Time-out Option ........................................................................ 7-1
Figure 7-2. Remote Digital Loopback .............................................................................. 7-2

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List of Figures

Figure 7-3. EIA Local Loopback Options ........................................................................ 7-3
Figure 7-4. EIA Remote Loopback Options .................................................................... 7-4
Figure 8-1. Editing Stored Phone Numbers .................................................................... 8-1
Figure 8-2. Enabling/Disabling the Auto Answer Function........................................ 8-2
Figure 9-1. Menu Path for Manual Command ............................................................... 9-1
Figure 10-1. Dial Options Menu ....................................................................................... 10-1
Figure 10-2. Path to Storing Numbers Option................................................................ 10-2
Figure 11-1. Normal Operation Before Initiating Loopback Test ................................ 11-1
Figure 11-2. Initiating a Test .............................................................................................. 11-2
Figure 11-3. Sample Test Status Displays........................................................................ 11-3
Figure 11-4. Complete Test Menu..................................................................................... 11-4
Figure 11-5. DTE & Loop Test ......................................................................................... 11-12
Figure 11-6. Initiating a DTE & Loop Test..................................................................... 11-13
Figure 11-7. Loop Only Test ............................................................................................ 11-14
Figure 11-8. Initiating a Loop Only Test ........................................................................ 11-15
Figure 11-9. DTE Only Test Diagram............................................................................. 11-16
Figure 11-10.Initiating a DTE Only Test ........................................................................ 11-17
Figure 11-11.DTE with Test Pattern................................................................................ 11-18
Figure 11-12.Initiating a DTE Test with Test Pattern ................................................... 11-19
Figure 11-13.Test Pattern Only........................................................................................ 11-20
Figure 11-14.Initiating a Test Using a Test Pattern....................................................... 11-21
Figure 11-15.Initiating a Self Test ................................................................................... 11-22
Figure 11-16.V.54 RDL with Test Pattern....................................................................... 11-23
Figure 11-17.Initiating a Remote Test ............................................................................ 11-24
Figure 12-1. Examples of Status Displays ....................................................................... 12-1
Figure D-1. EIA-232 Connector......................................................................................... D-1
Figure E-1. DDS Tail Circuit ..............................................................................................E-2
Figure E-2. Standard EIA-232-D Crossover Cable .........................................................E-3

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List of Tables
Table 4-1.

Configuration Methods ................................................................................. 4-2

Table 5-1.

Loop Rate Commands ................................................................................... 5-2

Table 5-2.

Network Address Command ....................................................................... 5-3

Table 5-3.

Remote Configuration Commands .............................................................. 5-4

Table 5-4.

Network Type Commands............................................................................ 5-5

Table 5-5.

Setting the Clock Source ................................................................................ 5-6

Table 6-1.

DTE Rate AT Commands .............................................................................. 6-2

Table 6-2.

Scrambler On/Off AT Commands .............................................................. 6-3

Table 6-3.

Data Format Commands ............................................................................... 6-6

Table 6-4.

Transmit Clock AT Commands.................................................................... 6-8

Table 6-5.

CS Options AT Commands......................................................................... 6-11

Table 6-6.

Short and Long Delays at Different Operating Speeds........................... 6-11

Table 6-7.

Anti-Stream AT Commands ....................................................................... 6-12

Table 6-8.

CD Options AT Commands........................................................................ 6-13

Table 6-9.

TR Options AT Commands......................................................................... 6-14

Table 6-10. SR Options AT Commands ......................................................................... 6-15
Table 6-11. Auxiliary Port AT Commands................................................................... 6-17
Table 6-12. DSU III AR Network Throughput ............................................................. 6-17
Table 7-1.

Test Timeout AT Commands........................................................................ 7-2

Table 7-2.

Remote Digital Loopback AT Commands .................................................. 7-2

Table 7-3.

EIA Local Loopback AT Commands ........................................................... 7-3

Table 7-4.

EIA Remote Loopback AT Commands ....................................................... 7-4

Table 8-1.

AT Command for Storing Phone Numbers................................................ 8-2

Table 8-2.

AT Commands for Auto Answer................................................................. 8-2

Table 9-1.

Manual Commands........................................................................................ 9-3

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List of Tables

Table 11-1. Messages from the DSU/CSU .................................................................... 11-5
Table 11-2. Troubleshooting New Installs..................................................................... 11-7
Table 11-3. AT Commands .............................................................................................. 11-9
Table 11-4. Test AT Commands.................................................................................... 11-10
Table 11-5. DTE With Test Pattern Commands.......................................................... 11-11
Table 11-6. Remote Tests and AT Commands............................................................ 11-23
Table A-1. RJ-48S Telco Connector Pinouts .................................................................. A-1
Table A-2. Primary EIA-232 Connector Pinouts........................................................... A-2
Table A-3. Primary V.35 Connector Pinouts ................................................................. A-3
Table A-4. Auxiliary EIA-232 Connector Pinouts ........................................................ A-4
Table B-1.

AT Commands ................................................................................................B-2

Table B-2.

Loop Rate Commands....................................................................................B-3

Table B-3.

Network Address Command........................................................................B-3

Table B-4.

Remote Configuration Commands ..............................................................B-3

Table B-5.

Network Type Commands............................................................................B-4

Table B-6.

Clock Source Commands...............................................................................B-4

Table B-7.

DTE Rate AT Commands ..............................................................................B-4

Table B-8.

Scrambler On/Off AT Commands...............................................................B-5

Table B-9.

Data Format Commands................................................................................B-5

Table B-10. Transmit Clock AT Commands ....................................................................B-5
Table B-11. CS Options AT Commands ...........................................................................B-6
Table B-12. Anti-Stream AT Commands .........................................................................B-6
Table B-13. CD Options AT Commands ..........................................................................B-7
Table B-14. TR Options AT Commands...........................................................................B-7
Table B-15. SR Options AT Commands ...........................................................................B-7
Table B-16. Secondary Rate AT Commands....................................................................B-8
Table B-17. Test Time-out AT Commands ......................................................................B-8
Table B-18. Remote Digital Loopback AT Commands ..................................................B-8
Table B-19. EIA Local Loopback AT Commands ...........................................................B-9
Table B-20. EIA Remote Loopback AT Commands .......................................................B-9
Table B-21. AT Command for Storing Phone Numbers ................................................B-9
Table B-22. AT Commands for Auto Answer .................................................................B-9
Table B-23. Test AT Commands......................................................................................B-10

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List of Tables

Table B-24. DTE With Test Pattern Commands............................................................B-11
Table B-25. Remote Tests and AT Commands..............................................................B-11
Table C-1. User Profiles ................................................................................................... C-1
Table C-2. Default Configuration Profiles .................................................................... C-2

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List of Tables

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Chapter 1

Introduction

PRODUCT OVERVIEW
The ADTRAN DSU III AR provides a reliable, high speed data
connection for customer Data Terminal Equipment (DTE) through
Digital Data Service (DDS) lines, DDS secondary channel services
(DDSII), or 4-wire Switched 56 network (SW56) lines.
The DSU III AR supports both synchronous and asynchronous data
communication over the DDS or 4-wire Switched 56 networks.
This unit is an all rate DSU/CSU, supporting services from 2.4 to 64
kbps including 19.2 and 38.4 kbps services. The DSU III AR may be
used in either point-to-point or multi-point circuits.
The DSU III AR provides both V.35 and EIA-232 electrical and
physical DTE interfaces to accommodate a variety of applications.
A second EIA-232 interface is provided for use on DDS lines with
secondary channel services.
To ensure a reliable connection, the unit features an extended
receiver capability which permits operation over long loops (3.4
miles or 5.5 km of 26 AWG at 56 kbps).
In addition to DDS, the unit supports Switched 56 (4-wire) service
with dialing accomplished from the front panel. This model is
compatible with AT&T Accunet and Sprint SW56 type services.
Figure 1-1 on page 1-2 shows a sample point-to-point application
for the DSU III AR.

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Chapter 1. Introduction

Router

DSU III AR
C
3
F
6

B
2
E
5

TFIHS
#

A
1
D
4

RETNE

DSU III AR
DDS
Network

UBD III USD

TST MLA DC DR

TFIHS

LECNAC

56 kbps

DSU III DBU

ENTER

RD CD ALM TST

A
1
D
4

B
2
E
5

SHIFT
#

SHIFT
CANCEL

Router

C
3
F
6

56 kbps

Figure 1-1. Sample Point-to-Point Application for DSU III AR

DDS Overview
Digital Data Service (DDS) is a nationwide service that allows
interconnection and transport of data at speeds up to 64 kbps. The
local exchange carriers provide the local loop service to DDS
customers and may provide data for routing Inter-LATA to an
interexchange carrier. In DDS mode, the DSU III AR supports all
DDS service rates yielding DTE rates of 2.4, 4.8, 9.6, 19.2, 38.4 (sync
or async), 56 and 64 kbps (synchronous). An additional rate of 57.6
kbps is available in async mode. At the DDS service rates of 56 kbps
and 64 kbps, the unit can be configured to run slower DTE rates
(async or sync). Secondary channel operation is supported at all
service rates up to 56 kbps, providing terminal rates of 75, 150, 300,
600, 1200, and 2400 bps. The secondary rates available depend on
the DDS service rate configured.

4-Wire Switched 56 Overview
This switched, 4-wire Digital Data Service allows customers to pay
for data connection only for the time the unit is active. The regional
operating companies provide the 4-wire local loop service to SW56
customers. In SW56 mode the DSU III AR supports DTE rates of
2.4, 4.8, 9.6, 19.2, 38.4 (asynchronous or synchronous) and 56 kbps
(synchronous). An additional DTE rate of 57.6 kbps is available in
asynchronous modes.

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Chapter 2

Installation

UNPACK, INSPECT, POWER UP
Carefully inspect the DSU III AR for any shipping damages. If
damage is suspected, file a claim immediately with the carrier and
contact ADTRAN Customer Service. If possible, keep the original
shipping container for use in shipping the DSU III AR for repair or
for verification of damage during shipment.

ADTRAN Shipments Include
The following items are included in ADTRAN shipments of the
DSU III AR:
•

DSU III AR unit

•

An 8-position modular to 8-position modular cable

•

The DSU III AR User Manual

Customer Provides
•

Male EIA-232 (standard 25-pin D-type), or

•

Male V.35 interface cable.

Pinouts for the rear connectors are included in Appendix A, Pinouts
on page A-1.

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Chapter 2. Installation

Power Up
Each DSU III AR unit is provided with a captive 8-foot power cord,
terminated by a three-prong plug which connects to a grounded
115 VAC power receptacle. A telco connector is also provided for
interface to the network.

Power to the DSU must be provided from a grounded 115 VAC, 60 Hz
receptacle.

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Chapter 2. Installation

REAR PANEL
The rear panel contains three DTE connectors which provide
primary channel V.35 or EIA-232, and a secondary channel EIA-232
port (auxiliary EIA -232). An 8-pin telco jack, a captive power cord,
and a power switch are also located on the rear panel. Pin
assignments for the DTE and network connections are listed in
Appendix A, Pinouts on page A-1. The DSU III AR rear panel is
shown in Figure 2-1.

2 Power Switch

1 Aux EIA-232

AUXILIARY EIA-232

3 Telco
Connection

PRIMARY V.35

OFF

PRIMARY EIA-232
TELCO
115 VAC
60HZ .15A

4 Primary EIA-232
Connector

No.

5 Primary V.35
Connector

Item

6 115 VAC
Connection

Function

Auxiliary EIA-232

Secondary channel services

Power Switch

Used to turn power on or off

Telco Connection

Connection to the dedicated circuit

Primary EIA-232

DTE interface

Primary V.35

High speed DTE interface

115 VAC Connection

Power cord connection
Figure 2-1. DSU III AR Rear View

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Chapter 2. Installation

Network Interface Connection
The DSU III AR has an eight-position modular jack labeled TELCO.
The connector is used for connecting to the network when the unit
is configured for either dedicated or switched operation. The pin
assignments for the telco connector are listed in Table A-1 on page
A-1.

DTE Data Connection/Primary DTE
The primary DTE rate is configured from the front panel. The
primary DTE can operate in asynchronous or synchronous modes
The primary DTE should be connected to either the EIA-232 DTE
connector or the CCITT V.35 DTE connector.
The maximum cable lengths recommended are 50 feet for the EIA232. The pin assignments for the primary EIA-232 connector are
shown in Table A-2 on page A-2. The EIA-232 connector works up
to 56 kbps with a low capacitance cable or with the external
transmit clock option selected.
For the CCITT V.35, the maximum cable lengths are 100 feet. The
pin assignments for the V.35 are shown in Table A-3 on page A-3.
The V.35 connector is recommended for use with data rates above
19.2 kbps.

To prevent possible radio frequency interference emissions, a shielded cable is required.

Secondary Channel Connection
If used, the secondary DTE should be connected to the auxiliary
EIA-232 connector. The pinout for the connector is shown in Table
A-4 on page A-4.

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Chapter 3

Operation

FRONT PANEL MENU STRUCTURE
The DSU III AR uses a multilevel menu approach to access its many
features. All menu operations are displayed in the LCD window.
The opening menu is the access point for all other operations. There
are four Main menu branches: Status, Test, Configuration and Dial.
Each main menu item has several functions and submenus to
identify and access specific parameters.

Main Menu
The following paragraphs briefly describe the main menu's four
branches, displayed on the front panel LCD (see Figure 3-1).
Detailed information is provided in the individual chapters for
each menu branch.

1 = STATUS

2 = TEST

3 = CONFIG

4 = DIAL

Figure 3-1. Main Menu LCD Display

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Chapter 3. Operation

Status
Status is used to display all relevant information for the network
and DTE interfaces. It displays the current operating mode, loop
status, rate of service from the network, DTE data rate and format,
and TR, SR, LL, and RL DTE interface lead status. The display
returns to the status menu when the front panel is not accessed. See
Chapter 12, Viewing Status Information on page 12-1 for more
detailed information.
Test
Test is used to control local and remote testing. Select local or
remote testing, and select the type of test and test pattern when
required. For more information see Chapter 7, Configuring Test
Options on page 7-1.
Configuration (Config)
Configuration is used to select network and DTE operating
parameters. This menu branch is divided into several chapters for
easier reference. The division includes a brief overview chapter
followed by a separate chapter for each of the five submenus of the
CONFIG branch: Network Configuration on page 5-1, Configuring
DTE Options on page 6-1, Configuring Test Options on page 7-1,
Configuring Dial Options on page 8-1, and Manual Command on page
9-1.
Dial
Dial provides manual dialing functions. Key in a number to dial,
select one of the ten stored numbers, or redial the last dialed
number. This menu is available for use only when AT&T/MCI
SW56 or US SPRINT SW56 is the selected network type. See
Chapter 10, Dial Selection on page 10-1 for more information.
The DIAL option is only available when the unit is configured for a
Switched 56 network type. For more information, see Chapter 10, Dial Selection on page 10-1.

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Chapter 3. Operation

Basic Menu Travel
Four function keys on the left side of the DSU III AR keypad allow
the various menu branches to be entered, exited, and scrolled
through. The four function keys are defined below.
Enter
Selects a displayed item.
Up Arrow
Scrolls up the submenu items.
Down Arrow
Scrolls down the submenu items.
Cancel
Exits (back one level) from the current branch of the menu.
To choose a menu item, press the corresponding number or alpha
character on the keypad (press Shift to activate alpha characters).
The item flashes on and off to show it is the currently selected
(active) choice. Press the up and down arrow keys to scroll through
the available menu items. Press Enter to select the flashing item.

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Chapter 3. Operation

The following Step/Action Table and Figure 3-2 illustrate how to
select the DSU III AR Loop Rate option.
Step

Action

To select CONFIGURATION (CONFIG), press 3; then Enter.

To select LOCAL or REMOTE test, press the corresponding
number; then press Enter.

Use the up and down arrows to view submenu items.

Choose an item on the submenu such as NETWORK OP(NETWORK OPT).

TIONS

Press 1 to select NETWORK OPT; then press Enter.

Press 1 to select LOOP RATE options; then press Enter.

When the current network loop rate flashes, you can
scroll up or down to view possible options.

To select a new loop rate, press the corresponding number; then press Enter.

.
1=LOOP RATE
1=LOCAL
3=CONFIG
2=REMOTE

1=NETWORK OPT.

2=NETWORK ADDR

2=DTE OPTIONS

3=REMOTE CONFIG.

3=TEST OPTIONS

4=NETWORK TYPE

4=DIAL OPTIONS

5=CLOCK SOURCE

5=MANUAL COMMAND

Figure 3-2. Example of Basic Menu Travel

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Chapter 3. Operation

FRONT PANEL
The DSU III AR faceplate is shown in Figure 3-3. Descriptions of
each part of the front panel follow the figure.

DSU III AR

ENTER

ALM TST

D
4

E
5

F
6

SHIFT
CANCEL

9
QUICK

Figure 3-3. DSU III AR Front View
LCD Window
Displays menu items and messages in 2 lines by 16 characters.
Enter
Selects active menu items. To activate a menu item, press the
number of the item. The menu item flashes, indicating it is the
active selection. Press Enter to select the menu item.
Numeric Keypad
The numeric keypad contains the numbers 0 through 9 and alpha
characters A through F, which are used to activate menu items and
enter parameters.
Up and Down Arrows
Use the up and down arrows to scroll through the submenu items
in the current menu. Submenu items appear two at a time in a
circular or wrapping fashion. The submenu items are displayed in
either a forward or reverse pattern.
Cancel
The Cancel key stops the current activity and returns to the
previous menu. Repeat until the desired menu level is reached.

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Chapter 3. Operation

Shift
To enter alpha characters, press Shift before each desired character.
To activate a menu item designated by an alpha character rather
than a number, press Shift, then the letter. The menu item flashes,
indicating which parameter is activated. Press Enter to select the
item.
If a key is pressed without using Shift, the numbered item becomes
active instead of the alpha item.
Quick
During most operations, the Quick key returns the display to the
main menu. During a test, the Quick key returns to the top of the
Test menu. In SW56 operation, if the unit is not in test, the Quick
key returns to the DIAL menu.

LED Descriptions
The DSU III AR has seven LED indicators, which are described
below.

3-6

REQUEST TO SEND

CLEAR TO SEND

TRANSMIT DATA

RECEIVE DATA

CARRIER DETECT

ALM

ALARM INDICATION

TST

TEST MODE MANUAL

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Chapter 4

Configuration Overview

LOCAL AND REMOTE CONFIGURATION
The DSU III AR can be configured locally using the front panel or
remotely by establishing communications with another DSU. The
front panel of the local DSU can then be used to configure the
remote DSU. During remote configuration, the DSU III AR prompts
for the remote address before continuing to the CONFIGURATION
(CONFIG) menus.
The CONFIGURATION menu consists of a group of five submenus
relating to a specific interface or function of the DSU III AR that
requires setup.
1=Network Opt.

Network Interface Parameters

2=DTE Options

DTE Interface Parameters

3=Test Options

Unit Test Options

4=Dial Options

Unit Dialing Options

5=Manual Command

ADTRAN Specific Commands

The DSU III AR contains four different user profiles (sets of
configurations options) that are stored in read-only memory (see
Appendix C, Default Configuration Profiles on page C-1). The unit is
shipped from the factory with profile number 1 (default
configuration) loaded into the current (nonvolatile configuration)
memory. If profile 1 matches requirements for the system, then no

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Chapter 4. Configuration Overview

additional configuration is required to put the unit into service. If
profile 1 does not match system requirements, it can be modified,
or one of the other profiles that more closely matches the system
requirements can be loaded into current memory. When a different
profile is loaded, or the existing profile is modified, it is stored in
the current (nonvolatile configuration) memory. The DSU III AR is
then configured with that profile every time power is turned on or
until the unit is reset.
For detailed information on configuration see Chapter 5, Network
Configuration on page 5-1, Chapter 6, Configuring DTE Options on
page 6-1, Chapter 7, Configuring Test Options on page 7-1, Chapter 8,
Configuring Dial Options on page 8-1, and Chapter 9, Manual
Command on page 9-1.

Configuration Methods
The DSU III AR responds to the following methods of
configuration:
•

VT-100 Compatible Terminal

•

AT Commands

•

V.25 Commands

•

Front Panel Commands

•

Remote Commands from another DSU running SLIP/PPP
protocol.

The DSU III AR provides methods for both local and remote
configuration. These methods are shown in Table 4-1.
Table 4-1. Configuration Methods
Stand Alone

4-2

Method

Local

Remote

AT Commands

Yes

V.25 Commands

Yes

Front Panel

Yes

DATAMATE

Yes

VT-100

Yes

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Chapter 4. Configuration Overview

A complete Configuration menu is shown in Figure 4-1; the
Configuration menu tree with DTE options is shown in Figure 4-2
on page 4-4.
1= AUTO
1= LOOP RATE
1= NETWORK OPT.
1= LOCAL

3=CONFIG

2= 2.4K

2= NETWORK ADDR

3= 4.8K

3= REMOTE CONFIG

4= 9.6K

4= NETWORK TYPE

5= 19.2K

5= CLOCK SOURCE

6= 38.4K
7= 56K

2= REMOTE

ENTER REMOTE
ADDRESS:0

8= 64K
2= DTE OPTIONS

1= DTE RATE

See Figure 4-2 on page 4-4

2= CONNECTOR TYPE

for a more detailed

3= DATA FORMAT

view of this section.

4= DTE CMD OPTION
5= TRANSMIT CLOCK
6= CS OPTIONS
7= ANTI-STREAM
8= CD OPTIONS
9= TR OPTIONS
A= SR OPTIONS
B= AUXILIARY PORT
ENTER TIMEOUT

3= TEST OPTIONS

1= TEST TIMEOUT

0 OFF: 00 SEC

2= RDL EN/DIS

1= RDL IGNORED
2= RDL ACCEPTED

4= DIAL OPTIONS

3= EIA LLB EN/DIS

1= DISABLED

4= EIA RLB EN/DIS

2= ENABLED

1= PHONE NUMBER

STORED NUMBER
TO EDIT (1-10):1

2= AUTO ANSWER

1= DISABLED
2= ENABLED

5= MANUAL COMMAND

COMMAND

COMMAND: HH
VALUE: 00

Figure 4-1. Complete Configuration Menu

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Chapter 4. Configuration Overview

1= DTE RATE

2= CONNECTOR TYPE

Options vary according to loop rate.

1= RS-232
2= V.35

2= DTE OPTIONS
3= DATA FORMAT

1= ASYNCHRONOUS
2= SYNCHRONOUS

1= ASYNC 9 BITS
2= ASYNC 10 BITS
3= ASYNC 11 BITS

1= DISABLED
4= DTE CMD OPTION

2= AT COMMAND SET
3= V.25 SYNC
4= V.25 BSC/ASYNC

5= TRANSMIT CLOCK

1= NORMAL
2= EXTERNAL
1= FORCED ON

6= CS OPTIONS

2= FOLLOWS RS
3= FOLLLOWS CD
4= FOLLOWS RS+ CD
5= OFF WITH LOCD

1= TIMER OFF
2= TIME 10 SECONDS

7= ANTI-STREAM

3= TIME 30 SECONDS
4= TIME 60 SECONDS

1= FORCED ON
8= CD OPTIONS

2= NORMAL
3= OFF WITH LOCD

9= TR OPTIONS

1= IGNORED
2= IDLE WHEN OFF

1= FORCED ON

3= OFF>ON DIAL #1

2= OFF OOS ONLY

4= OFF>ON DIAL #2

3= OFF LOCD ONLY

A= SR OPTIONS

4= OFF TEST ONLY
5= OFF TEST +OOS
1= EIA-232

B= AUXILIARY PORT

6= OFF TEST + LOCD

2= V.35

Figure 4-2. Configuration Menu with DTE Options

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Chapter 4. Configuration Overview

VT-100 Connection
The DSU III AR can be configured and controlled over a direct EIA232 connection to the Auxiliary Port located on the back of the unit.
To set up the DSU III AR for a VT-100 terminal session, the
following steps are required:
Step
1.

Action
From the front panel set the connection baud rate. Follow the
menu below to display the appropriate configuration
parameters. Select one of the CONTROL baud rates.
1= DTE RATE

3= CONFIG 1= LOCAL

2= DTE OPTIONS

2=REMOTE ENTER ADDRESS

2= CONNECTOR TYPE
3= DATA FORMAT

1= 1.2K AT_CMD

4= DTE CMD OPTION

2= 75 SEC

5=TRANSMIT CLOCK

3= 150 SEC

6= CS OPTIONS

4= 300 SEC

7= ANTI-STREAM

5= 600 SEC

8= CD OPTIONS

6= 1.2K SEC

9= TR OPTIONS

7= 2.4K SEC

A= SR OPTIONS

8= OFF

B= AUXILIARY PORT

9= 300 CONTROL
A= 1.2K CONTROL
B= 2.4K CONTROL
C= 9.6K CONTROL

61202011L1-1

After the baud rate is selected, a passcode prompt is displayed.
Enter the desired passcode, or press Enter to accept the 123
default.

Configure the VT-100 emulator with the appropriate baud rate,
8 DATA BITS, NO PARITY BITS, 1 STOP BIT, and NO FLOW control
(8N1). Refer to the VT-100 emulator documentation for details
on configuration.

Connect the VT-100 terminal to the female RS-232 connector,
labeled AUXILIARY PORT, located on the back of the unit.

Press on the VT-100 terminal and a passcode prompt is
displayed. Enter the passcode from step 2.

DSU III AR User Manual

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Chapter 4. Configuration Overview

AT Commands
The DSU III AR can be configured and controlled with in-band AT
commands from an asynchronous DTE port just as modems are.
To exit the data mode and enter the command mode, the
asynchronous DTE device must transmit a proper escape sequence
or three pluses (+++) to the DSU III AR. A specified time delay
must occur between the last data character and the first escape
sequence character. This is the guard time delay, and it can be
changed by writing 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 escape code character three times in
succession with delay between each character being less than the
guard time.
Once the command mode is entered, AT commands can be
transmitted to the DSU III AR to configure most of the options or
initiate tests to check both the DSU III AR and the network
connections. All command lines must begin with the AT attention
code in either capital or lower case letters. The command that
follows must match the case of the attention code.
The command line may contain a single command or a series of
commands after the AT attention code. When a series of commands
is 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 DSU III AR 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 backspace character (ASCII 008) to erase
errors so the proper commands can be entered.
Valid AT commands for the DSU III AR are listed in Appendix B,
AT Commands on page B-1.

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Chapter 4. Configuration Overview

V.25 Bis Commands
When configured for the V.25 bis option, the DSU III AR accepts inband dialing and configuration commands from both synchronous
and asynchronous DTE ports.
The V.25 bis option supports the following protocols:
•

SDLC (Synchronous Data Link Control)

•

BI-SYNC

•

ASYNCHRONOUS

SDLC Option
Character Format
•

Data bits - 8

•

Parity bit - Ignored

Command Structure
[F][A][C][V.25 bis COMMAND][FCS][F]
The address field [A] is FFH. The control field [C] is set to 13H
except for cases of multi-frame responses. For this case, the control
field is set to 03H in all but the last frame. The 03H in the control
field indicates that other frames are to follow while the 13H in the
control field indicates the final frame.
Bi-Sync Option
Character Format
•

Data bits - 7

•

Parity bit - Odd

Command Structure
[SYN][SYN][STX][V.25 bis COMMAND][ETX]

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Chapter 4. Configuration Overview

Asynchronous Option
Character Format
Start bit - 1
Data bits - 7
Parity bit - Even
Stop bit - 1
Command Structure
[V.25 bis COMMAND][CR][LF]
Command Descriptions
The ADTRAN V.25 bis command set is a subset of the CCITT V.25
bis command set. In addition to the CCITT commands supported,
ADTRAN has added configuration commands for both local and
remote DSUs.
The ADTRAN V.25 bis command set follows:

4-8

CIC

Connect incoming call

CNL

Configuration local

CNR

Configuration remote

CRN

Call request with number

CRS

Call request using stored number

DIC

Disregard incoming call

PRN

Program number

RLN

Request list of numbers

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Chapter 4. Configuration Overview

The following list contains possible responses to V.25 bis
commands:
VAL

Valid V.25 command processed

CFIET

Call failed on switched network - busy detected

CFIDE

Call failed on switched network - no wink detected

CFINS

Call failed - no dial string in specified register

INVCU

Unknown command detected

INVPS

Invalid parameter syntax

INVPV

Invalid parameter value

INVBL

Invalid local password

INVBM

Invalid remote password

INC

Incoming call

CNX

Call connected

If verbose responses are disabled (ATV0), the following list of threecharacter responses are the only ones returned:
VAL

Valid V.25 command processed

INV

Invalid command received

CFI

Call failed

INC

Incoming call

CNX

Call connected

Syntax and Possible Responses
CIC (Connect Incoming Call)
This command causes the DSU to go on-line. For dial backup units,
this command hangs up the dial backup line and initiates an
attempt to reestablish the main (DDS) line. There are no parameters
associated with this command. Possible indications include VAL,
CNX, and CFIxx.

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Chapter 4. Configuration Overview

CNL (Configuration Local)
This command is used to pass AT commands to the local modem
via the V.25 bis command processor. This allows the DSU III AR to
be configured with AT commands via a synchronous interface. The
command has the following format:
CNL[LOCAL PASSWORD;]AT[ONE OR MORE AT COMMANDS]
A local password may not be required, depending on the present
configuration of the unit. Responses to CNL commands are
returned in the data format currently configured. Possible
responses include VAL and INVn.
CNR (Configuration Remote)
This command is used to pass AT commands over the network to
the remote DSU via the V.25 bis command processor. This allows a
remote DSU III AR to be configured from a synchronous interface.
The command's format is as follows:
CNR[REMOTE PASSWORD;]AT[ONE OR MORE AT COMMANDS]
The remote password may or may not be required depending on
the present configuration of the remote unit. Responses to the CNR
commands are returned in the data format currently configured.
Possible responses include VAL and INVn.
Switched 56 Operation
CRN (Call Request with Number)
When the DSU III AR is configured for SW56 operation, the CRN
command causes the DSU to dial the supplied number. The
command's format follows:
CRN[NUMBER TO BE DIALED]
If no number is included in the command, the number stored in
dial register number 1 is dialed. If no number is provided and no
number is stored in dial register number 1, the DSU III AR
responds with the call failure indication CFINS (Call Failure
Indication Not Stored).
For a DBU unit, this command initiates dialing on the backup
circuit. If the number supplied contains non-dialable digits, they

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Chapter 4. Configuration Overview

are ignored and only the dialable digits are dialed. Possible
responses include VAL, CNX, and CFIxx.
CRS (Call Request Using Stored Number)
The CRS command causes the DSU III AR to dial the number
stored in the specified register. The format of this command is as
follows:
CRS [OPTIONAL SPACE][REGISTER NUMBER 1-10]
If this command is issued without the register number parameter,
the INVPS (Invalid Parameter Syntax) response is issued. If this
command is issued and the register parameter is not in the valid
range for dialing registers, the INVPV (Invalid Parameter Value)
response is returned. Other responses include VAL, CNX, and
CFIxx.
DIC(Disregard Incoming Call)
This command causes the V.25 bis processor to return to command
mode even if there is an incoming call pending. This allows local
commands to be issued and incoming calls to be ignored. There are
no parameters associated with this command. The DSU responds
with VAL.
PRN (Program Number)
This command stores the supplied number into the specified
register. The command has the following format:
PRN REGISTER NUMBER;[NUMBER TO BE STORED]
If this command is entered with no parameters, the INVPS
response is returned. If no register number is included in the
command or if it is invalid, the INVPV response is returned. This
response is also returned if the number to be stored contains invalid
characters. The characters 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, P, T, and & are
valid dial characters. If no digits are issued with this command, the
specified register is cleared. The DSU responds with VAL.

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Chapter 4. Configuration Overview

RLN (Request List of Numbers)
This command causes the DSU III AR to return the number stored
in the specified register. The format of this command follows:
RLN

[REGISTER NUMBER]

If the register number is invalid, the INVPV response is returned.
When a correct register number is entered, the following response
is returned:
LSN

[REGISTER NUMBER];[NUMBER STORED]VAL

If no register number is present in the command, the DSU III AR
responds with a list of all the registers and the stored numbers. This
list is followed by the VAL response.

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Chapter 5

Network Configuration

NETWORK OPTIONS
The NETWORK OPTIONS configuration parameters control the loop
operation of the DSU III AR.
Once a parameter is set, COMMAND ACCEPTED is displayed briefly
before returning to the active menu.

Loop Rate
The Loop Rate option sets the loop operating speed. The unit
should be set to the rate required by the DDS Service. The DSU III
AR also supports subrate DTE data over a 56 kbps or 64 kbps loop.
The loop rate must be set independently of the DTE rate.
The default factory setting is AUTO. When configured to AUTO, the
DSU will automatically attempt to adapt to the loop rate. Since 64k
and 56k secondary channels look identical on the network, the DSU
III will adapt to 56k secondary channel for either loop rate. If the
loop rate is known, select the rate from the menu. The various loop
rates and format selections are listed in Figure 5-1 on page 5-2. The
equivalent AT commands that perform the same configuration
functions are shown in Table 5-1 on page 5-2.
Eight loop rate selections are available (shown in Figure 5-1). After
selecting any loop rate other than AUTO or 64 KBPS the option for a
secondary channel is available. The secondary channel rate is
determined by the current loop rate.

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Chapter 5. Network Configuration

1= AUTO

1=NETWORK OPT.
1=LOCAL

3=CONFIG

2=REMOTE

ENTER ADDRESS

1= LOOP RATE

2= 2.4K

2= NETWORK ADDR

3= 4 .8K

1= NO SEC CH

3= REMOTE CONFIG

4= 9.6K

2= SEC CHANNEL

4= NETWORK TYPE

5= 19.2K

5= CLOCK SOURCE

6= 38.4K

2=DTE OPTIONS

7= 56K

3=TEST OPTIONS

8= 64K

4=DIAL OPTIONS
5=MANUAL COMMAND

Figure 5-1. Setting Loop Rate Options
Table 5-1. Loop Rate Commands
Front Panel

5-2

AT Command

AUTO

%B0

2.4K with no secondary channel

%B1

4.8K with no secondary channel

%B2

9.6K with no secondary channel

%B3

19.2K with no secondary channel

%B4

38.4K with no secondary channel

%B5

56K with no secondary channel

%B6

64K clear channel

%B7

2.4K with secondary channel

%B9

4.8K with secondary channel

%B10

9.6K with secondary channel

%B11

19.2K with secondary channel

%B12

38.4K with secondary channel

%B13

56K with secondary channel

%B14

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Chapter 5. Network Configuration

Network Address
A two-digit decimal address can be assigned to each DSU III AR.
This addressing capability makes it possible to perform remote
configuration and testing in point-to-point and multi-drop
networks. Figure 5-2 shows the menu path used to change the
network address. The factory default address setting is 0. Table 5-2
shows the AT commands used to set the network address.
1=LOOP RATE
1=NETWORK OPT.
1=LOCAL

2=NETWORK ADDR

ENTER NETWORK

3=REMOTE CONFIG

ADDRESS: 0

4=NETWORK TYPE
3=CONFIG

5=CLOCK SOURCE
2=DTE OPTIONS
2 =REMOTE ENTER
ADDRESS

3=TEST OPTIONS
4=DIAL OPTIONS
5=MANUAL COMMAND

Figure 5-2. Setting the Network Address
Table 5-2. Network Address Command
Front Panel
XX (Decimal)

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AT Command

Description

_N=xx

Assigns a 2-digit Network Address

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Chapter 5. Network Configuration

Remote Configuration
This option sets up the DSU III AR to accept or reject remote
configuration commands. Figure 5-3 shows the menu path for
enabling/disabling remote configuration. The factory
default setting is ENABLED.
1= LOOP RATE
1= NETWORK OPT.
1= LOCAL
3= CONFIG

2= NETWORK ADDR
3= REMOTE CONFIG

1= DISABLED

4= NETWORK TYPE

2= ENABLED

5= CLOCK SOURCE
2= DTE OPTIONS
2= REMOTE ENTER

3= TEST OPTIONS

ADDRESS

4= DIAL OPTIONS
5= MANUAL COMMAND

Figure 5-3. Enabling/Disabling Remote Configuration

Table 5-3 shows the equivalent AT commands used to enable or
disable remote configuration.
Table 5-3. Remote Configuration Commands
Front Panel

5-4

AT Command

Description

1=DISABLE

&P4

Disable Remote Configuration

2=ENABLE

&P5

Enable Remote Configuration

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Chapter 5. Network Configuration

Network Type
This option configures the DSU III AR for the specific type of
network being used. The choices are DEDICATED, AT&T/MCI SW56,
and US SPRINT SW56. The factory default setting is
DEDICATED (see Figure 5-4).

1= LOOP RATE
1= NETWORK OPT.
1= LOCAL
3=CONFIG

2= NETWORK ADDR.
3= REMOTE CONFIG

1= DEDICATED

4= NETWORK TYPE

2= AT&T/MCI SW 56

5= CLOCK SOURCE

3= US SPRINT SW 56

2= DTE OPTIONS
2= REMOTE ENTER

3= TEST OPTIONS

ADDRESS 4= DIAL OPTIONS
5= MANUAL COMMAND

Figure 5-4. Setting Network Type Options

When AT&T/MCI SW56 or US SPRINT SW56 is selected, the Main
menu displays the DIAL selection.
Table 5-4 shows the equivalent AT commands that perform the
same configuration functions.
Table 5-4. Network Type Commands
Front Panel

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AT Command Description

1=DEDICATED &L0

Any 4-wire DDS Network

2=AT&T/MCI

&L1

AT&T/MCI Switched 56 Service

3=US SPRINT

&L2

US SPRINT Switched 56 Service

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Chapter 5. Network Configuration

Clock Source
The CLOCK SOURCE options specify the timing source for the DSU
III AR internal circuitry. The choices are FROM NETWORK and
MASTER. The factory default setting is FROM NETWORK (see Figure
5-5).
1= LOOP RATE
1= NETWORK OPT.
1= LOCAL

2= NETWORK ADDR
3= REMOTE CONFIG

3=CONFIG

4= NETWORK TYPE

1= MASTER

5= CLOCK SOURCE

2= FROM NETWORK

2= DTE OPTIONS
2= REMOTE ENTER
ADDRESS

3= TEST OPTIONS
4= DIAL OPTIONS
5= MANUAL COMMAND

Figure 5-5. Setting the Clock Source
When operating on a DDS network, the timing should be from the
most stable clock source, usually FROM NETWORK. On a point-topoint private network, one DSU III AR must be set for MASTER and
the other set for FROM NETWORK. Table 5-5 shows the equivalent AT
commands for setting the clock source.
When the DSU III AR is set as the master clock source, it will
default to its internal oscillator as the clock reference. To enable the
External DTE port as the reference clock for the circuit, see Chapter
6, Configuring DTE Options on page 6-1.

Table 5-5. Setting the Clock Source
Front Panel
1=MASTER
2=FROM NETWORK

5-6

AT Command Description
_X0
_X1

DSU is the master timing source
Network RX Signal is timing source

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Chapter 6

Configuring DTE Options

DTE OPTIONS
The DTE OPTIONS menu is used to select the configuration
parameters that control the operation of the DSU III AR's DTE
Interface such as the DTE rate, connector type, data format, DTE
command options, transmit clock, CS options, anti-stream, and CD
options.

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Chapter 6. Configuring DTE Options

DTE Rate
The selectable DTE rates over a 56 or 64 kbps loop with no
secondary channel are shown in Figure 6-1. If a slower loop rate is
selected, then the DTE rate automatically matches the loop rate. If
an attempt is made to set the DTE rate for loop rates slower than 56
kbps, the DSU III AR briefly displays DTE RATE SAME AS THE
NETWORK before returning to the status screen. The factory default
setting is SAME AS LOOP.
1= NETWORK OPT.

1= 2.4K
1= DTE RATE

2= 4.8K

2= CONNECTOR TYPE

4= 19.2K

3= DATA FORMAT

5= 38.4K

3= 9.6K
1= LOCAL
2= DTE OPTIONS

3=CONFIG

2= REMOTE ENTER ADDRESS

4= DTE CMD OPTION

6= 56K/57.6K

For 64Kbps Loop

5= TRANSMIT CLOCK

7= SAME AS LOOP

1= SCRAMBLER OFF

6= CS OPTIONS

2= SCRAMBLER ON

3= TEST OPTIONS

7= ANTI-STREAM

3= DATA INVERT

4= DIAL OPTIONS

8= CD OPTIONS

5= MANUAL

9= TR OPTIONS
A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-1. DTE Rates for 56 or 64 kbps Loop Rate with No Secondary Channel

The equivalent AT commands for setting the DTE rate for a 56 kbps
loop rate with no secondary channel are shown in Table 6-1.
Table 6-1. DTE Rate AT Commands

6-2

Front Panel

AT Command Description

1=DTE 2.4K

%K3

DTE rate 2.4K sync and async

2=DTE 4.8K

%K4

DTE rate 4.8K sync and async

3=DTE 9.6K

%K5

DTE rate 9.6K sync and async

4=DTE 19.2K

%K6

DTE rate 19.2K sync and async

5=DTE 38.4K

%K7

DTE rate 38.4K sync and async

6=DTE 56K/57.6K

%K8

DTE rate 56K sync or 57.6 async

7=SAME AS LOOP

%K9

DTE rate same as loop speed

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Chapter 6. Configuring DTE Options

If the DSU III AR is set for a loop rate of 56 kbps with secondary
channel, then SCRAMBLER ON/OFF options are available as shown
in Figure 6-2. The factory default setting is SCRAMBLER OFF.
1= NETWORK OPT.
1= LOCAL

2= DTE OPTIONS

2= 4.8K

2= CONNECTOR TYPE

3= 9.6K

3= DATA FORMAT

4= 19.2K

4= DTE CMD OPTION

5= 38.4K

1= SCRAMBLER OFF

5= TRANSMIT CLOCK

6= 56K/57.6K

2= SCRAMBLER ON

3= TEST OPTIONS

6= CS OPTIONS

7= SAME AS LOOP

3= DATA INVERT

4= DIAL OPTIONS

7= ANTI-STREAM

3=CONFIG

2= REMOTE ENTER
ADDRESS

1= 2.4K
1= DTE RATE

5= MANUAL

56 Kbps Secondary
Channel Loop Rates

8= CD OPTIONS
9= TR OPTIONS
A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-2. DTE Rates for 56 kbps Secondary Channel and 64 kbps Loop Rates

Table 6-2 shows the equivalent AT commands for setting
SCRAMBLER ON/OFF for loop rates of 56 kbps with secondary
channel and 64 kbps.
Table 6-2. Scrambler On/Off AT Commands
Front Panel

AT Command

Description

1=SCRAMBLER OFF _F0

DTE data scrambler disabled

2=SCRAMBLER ON

_F1

DTE data scrambler enabled

3=DATA INVERT

_F2

DTE data invert enabled (56 kbps secondary channel Loop Rate only). LBE codes
from DTE suppressed (64 kbps only).

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Chapter 6. Configuring DTE Options

For point-to-point operation at 56 kbps with secondary channel, the network requires that the primary and secondary channel data not be all zeros
simultaneously. For HDLC protocol applications, this constraint can be
eliminated by selecting either the DATA INVERT option or the SCRAMBLER ON option. The factory default setting is SCRAMBLER OFF.

For 64 kbps clear channel operation, there is a possibility that the DTE
data sequences might mimic network loop maintenance functions and erroneously cause other network elements to activate loopbacks. To prevent
this, the SCRAMBLER ON or SUPPRESS LBE option should be selected
for both the local and remote DSU III AR.

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Chapter 6. Configuring DTE Options

Connector Type
The CONNECTOR TYPE option is used to specify which of the
primary channel connectors is used to connect to the DTE. Figure
6-3 shows the menu path used to set the connector type. The
factory default setting is V.35. There are no AT commands available
to set the connector type.
1= NETWORK OPT.
1= LOCAL
2= DTE OPTIONS

1=DTE RATE

1= RS-232

2= CONNECTOR TYPE

2= V.35

3= DATA FORMAT
3=CONFIG

4= DTE CMD OPTION
5= TRANSMIT CLOCK
2= REMOTE

ENTER ADDRESS

3= TEST OPTIONS

6= CS OPTIONS

4= DIAL OPTIONS

7= ANTI-STREAM

5= MANUAL

8= CD OPTIONS
9=TR OPTIONS
A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-3. Selecting the Connector Type

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Chapter 6. Configuring DTE Options

Data Format
The DATA FORMAT option is used to select either the SYNCHRONOUS
or ASYNCHRONOUS mode of operation for the DTE interface. The
factory default setting is SYNCHRONOUS (see Figure 6-4). If
ASYNCHRONOUS is chosen, the length of the data bytes must be
selected.
1= NETWORK OPT.
1= DTE RATE
2= DTE OPTIONS
1= LOCAL

1= ASYNC 9 BITS

2= CONNECTOR TYPE

1= ASYNCHRONOUS

2= ASYNC 10 BITS

3= DATA FORMAT

2 = SYNCHRONOUS

3 = ASYNC 11 BITS

4= DTE CMD OPTION
5= TRANSMIT CLOCK
3=CONFIG

6= CS OPTIONS
7= ANTI-STREAM
2= REMOTE ENTER
ADDRESS

3= TEST OPTIONS

8= CD OPTIONS

4= DIAL OPTIONS

9= TR OPTIONS

5= MANUAL COM.

A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-4. Selecting Asynchronous or Synchronous Data Format
Table 6-3 shows the AT commands that can be used to set the DATA
FORMAT.
Table 6-3. Data Format Commands
Front Panel

AT Command Description

1=ASYNCHRONOUS

&Q0

Always asynchronous

2=SYNCHRONOUS

&Q2

Always synchronous

For asynchronous options, select the length of the data bytes.

6-6

1=ASYNC 9 BITS

N/A

9 bits including start, stop, parity

2=ASYNC 10 BITS

N/A

10 bits including start, stop, parity

3=ASYNC 11 BITS

N/A

11 bits including start, stop, parity

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Chapter 6. Configuring DTE Options

DTE Command Option
The DTE COMMAND option is used to enable AT commands from
the DTE, enable V.25 bis SDLC (Synchronous Data Link Control)
commands, enable V.25 (Bisync and Async), or disable all DTE
command modes (see Figure 6-5).
1= NETWORK OPT.
1= LOCAL

1= DTE RATE
2= CONNECTOR TYPE
3= DATA FORMAT

3=CONFIG

2= DTE OPTIONS

2 =REMOTE ENTER
ADDRESS

4= DTE CMD OPTION

1= DISABLED

5= TRANSMIT CLOCK

2= AT COMMAND SET

3= TEST OPTIONS

6= CS OPTIONS

3= V.25 SYNC

4= DIAL OPTIONS

7= ANTI-STREAM

4= V.25 BSC/ASYNC

5= MANUAL COM.

8= CD OPTIONS
9= TR OPTIONS
A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-5. Selecting DTE Command Option

When the unit is in DTE CMD OPTION mode (idle in SW56 mode, forced
with TR option, or from escape sequence in AT mode) with AT COMMAND
SET or V.25 SYNC selected, the DTE format is independent of the DATA
FORMAT option. However, if V.25 BSC/ASYNC is selected, the unit will
use V.25 BISYNC (BSC) commands for synchronous data format or V.25
ASYNC commands for asynchronous data format.

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Chapter 6. Configuring DTE Options

Transmit Clock
The TRANSMIT CLOCK option is used to select the source of the clock
used to transfer data from the DTE into the DSU III AR. Figure 6-6
shows the menu path used to set the TRANSMIT CLOCK option. The
factory default in NORMAL.
1= NETWORK OPT.
1= DTE RATE
2= CONNECTOR TYPE
1= LOCAL

3= DATA FORMAT
4= DTE CMD OPTION
2= DTE OPTIONS

3= CONFIG

5= TRANSMIT CLOCK

1= NORMAL

6= CS OPTIONS

2= EXTERNAL

7= ANTI-STREAM
2= REMOTE

ENTER ADDRESS

3= TEST OPTIONS

8= CD OPTIONS

4= DIAL OPTIONS

9= TR OPTIONS

5= MANUAL COM.

A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-6. Transmit Clock Options
Table 6-4 shows the AT commands used to set the TRANSMIT CLOCK
option.
Table 6-4. Transmit Clock AT Commands
Front Panel

AT Command

Description

1=NORMAL

&X0

TX clock from DSU selected

2=EXTERNAL

&X1

ETC clock from DTE selected

The EXTERNAL CLOCK option allows the DSU III AR to accept
MASTER CLOCK timing from the External DTE Port as defined
under DTE Options connector type. The CLOCK SOURCE under
NETWORK OPTIONS must also be set to MASTER as noted in Network
Configuration on page 5-1.

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Chapter 6. Configuring DTE Options

The EXTERNAL CLOCK option is normally used in modem tail circuit
applications. See Appendix E, DSU to DSU Tail Circuit on page E-1
for information about the DSU to modem interconnect diagram for
this application.
The EXTERNAL CLOCK option is also recommended when the
EIA-232 connector is used for 56 kbps and 64 kbps applications. A
special DSU cable diagram for this application is shown in
Appendix D, EIA-232 Connector on page D-1. Using this option and
special cable eliminates data errors caused by excessive delays in
the DTE transmit clock receiver and transmit data driver.

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Chapter 6. Configuring DTE Options

CS Options
The CLEAR TO SEND (CS OPTIONS) menu is used to select one of five
different control modes for the CS lead. Figure 6-7 shows the menu
path used to access the CS OPTIONS menu. The default factory
setting is FOLLOWS RS with CS DELAY SHORT.
1= NETWORK OPT.
1= LOCAL

1= DTE RATE
2= DTE OPTIONS

2= CONNECTOR TYPE
3= DATA FORMAT

3=CONFIG

2= REMOTE

4= DTE CMD OPTION

1= FORCED ON

1= CS DELAY SHORT

5= TRANSMIT CLOCK

2= FOLLOW RS

2= CS DELAY LONG

ENTER

3= TEST OPTIONS

6= CS OPTIONS

3= FOLLOWS CD

ADDRESS

4= DIAL OPTIONS

7= ANTI-STREAM

4= FOLLOWS RS+CD

1= CS DELAY SHORT

8= CD OPTIONS

5= OFF THE LOCD

2= CS DELAY LONG

5= MANUAL COM.

9= TR OPTIONS
A= SR OPTIONS
B= AUXLILARY PORT

Figure 6-7. Selecting CS Options
If one of the options chosen involves request to send (RS), then the
delay from RS to CS must be selected. Table 6-5 on page 6-11 shows
the AT COMMANDS used to set the CS OPTIONS.

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Chapter 6. Configuring DTE Options

Table 6-5. CS Options AT Commands
Front Panel

AT Command Description

1=FORCED ON

&R0

CS always on.

2=FOLLOWS RS

&R1

CS on with RS after delay; off when RS
or if DSU cannot pass data.

3=FOLLOWS CD

&R2

CS off when CD goes off or if DSU cannot pass data.

4=FOLLOWS RS+CD

&R3

CS follows RS after delay and also off if
CD off. If CD goes off after RS is on, DSU
III AR will turn off CS but continue to pass
data until RS goes off. CS also off if DSU
cannot pass data.

5=OFF WITH LOCD

&R4

Off 5 sec after LOCD. Valid only in SW56
mode. CS is forced on but will turn off for
5 seconds after a call is disconnected.

For RS options, select the RS to CS delay length.
1=CS DELAY SHORT

_D0

Short Delay from RS to CS selected.

2=CS DELAY LONG

_D1

Long Delay from RS to CS selected.

Specified times for the short and long delays at the different
operating speeds are shown in Table 6-6.
Table 6-6. Short and Long Delays at Different Operating Speeds
Rate

Short Option

Long Option Tolerance

Add to Maximum Time
for Secondary Channel

64K

1.1ms

16.1ms

±.4ms

56K

1.1ms

16.1ms

±.4ms

.33ms

38.4K

1.5ms

16.5ms

±.4ms

.63ms

19.2K

1.5ms

16.5ms

±.4ms

1.25ms

9.6K

1.5ms

16.5ms

±.4ms

2.5ms

4.8K

1.9ms

16.9ms

±.7ms

5.0ms

2.4K

3.8ms

18.8ms

±1.3ms

10.0ms

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Chapter 6. Configuring DTE Options

Anti-Stream
The ANTI-STREAM option is used to select the anti-stream time-out.
The anti-stream time-out is the maximum time the DSU III AR
transmits data into the network from the DTE. This feature
prevents one DTE device on a multi-drop network from
continuously tying up the transmit circuit back to the master DSU.
Figure 6-8 shows the menu path used to access the ANTI-STREAM
options menu.
The anti-stream timer is reset to zero when RS changes to the active
state and is updated every second while RS is active. When the
anti-stream time-out expires, the DSU III AR stops transmitting
DTE data into the network but continues to accept data from it.
This condition exists until the DTE deactivates the RS input.
1= NETWORK OPT
1= LOCAL

1= DTE RATE
2= DTE OPTIONS

2= CONNECTOR TYPE
3= DATA FORMAT

3= CONFIG
2= REMOTE ENTER
ADDRESS

4= DTE CMD OPTION

1= TIMER OFF

5= TRANSMIT CLOCK

2= TIME 10 SEC.

3= TEST OPTIONS

6= CS OPTIONS

3= TIME 30 SEC.

4= DIAL OPTIONS

7= ANTI-STREAM

4= TIME 60 SEC.

5= MANUAL COM.

8= CD OPTIONS
9= TR OPTIONS
A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-8. Anti-Stream Options
The factory default setting is TIMER OFF. Table 6-7 shows the
available options and their AT commands.
Table 6-7. Anti-Stream AT Commands

6-12

Front Panel

AT Command Description

1=TIMER OFF

%T0

Anti-stream timer disabled

2=TIME 10 SEC.

%T1

Time-out equal 10 seconds

3=TIME 30 SEC.

%T2

Time-out equal 30 seconds

4=TIME 60 SEC.

%T3

Time-out equal 60 seconds

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Chapter 6. Configuring DTE Options

Carrier Detect (CD) Options
The CARRIER DETECT (CD) OPTIONS menu is used to select one of
three different control modes for the receive line signal detector
(CD) lead. The default factory setting is NORMAL (see Figure 6-9).
1= NETWORK OPT.
1= LOCAL

1= DTE RATE
2= DTE OPTIONS

2= CONNECTOR TYPE
3= DATA FORMAT

3= CONFIG

4= DTE CMD OPTION
5= TRANSMIT CLOCK
2= REMOTE ENTER ADDRESS 3= TEST OPTIONS

6= CS OPTIONS

4= DIAL OPTIONS

7= ANTI-STREAM

5= MANUAL COM.

8= CD OPTIONS

1= FORCED ON
2= NORMAL

9= TR OPTIONS

3= OFF WITH LOCD

A= SR OPTIONS
B= AUXILIARY PORT

Figure 6-9. Selecting CD Options
Table 6-8 shows the equivalent AT commands for setting CD
options.
Table 6-8. CD Options AT Commands
Front Panel

AT Command

Description

1=FORCED ON

&C0

On all the time

2=NORMAL

&C1

On only when data present on loop.

3=OFF WITH LOCD

&C2

On except after disconnect in Switched
56 application

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Chapter 6. Configuring DTE Options

TR Options
The TR OPTIONS menu is used to select the DSU III AR response to
the data terminal ready (TR) lead. The factory default setting is
IGNORED (see Figure 6-10).
1= NETWORK OPT.
1= LOCAL

1= DTE RATE
2= DTE OPTIONS

2= CONNECTOR TYPE
3= DATA FORMAT

3= CONFIG

4= DTE CMD OPTION
5= TRANSMIT CLOCK
2= REMOTE ENTER ADDRESS

3= TEST OPTIONS

6= CS OPTIONS

4= DIAL OPTIONS

7= ANTI-STREAM

1= IGNORED

5= MANUAL COM.

8= CD OPTIONS

2= IDLE WHEN OFF

9= TR OPTIONS

3= OFF> ON DIAL #1

A= SR OPTIONS

4= OFF> ON DIAL #2

B= AUXILIARY PORT

Figure 6-10. Selecting TR Options
Table 6-9 shows the equivalent AT commands for setting
TR OPTIONS.
Table 6-9. TR Options AT Commands
Front Panel
1=IGNORE

AT Command Description
&D0

Ignore the TR input.

2=IDLE WHEN OFF &D2

See the following note.

3=OFF>ON DIAL #1 &D3

Dial Stored #1: TR goes off to on (SW56 only).

4=OFF>ON DIAL #2 &D4

Dial Stored #2: TR goes off to on (SW56 only).

For IDLE WHEN OFF option: In SW56 mode, TR off will cause the DSU to go
On Hook (Idle). The unit also will not dial out if TR is off. In dedicated mode,
the DSU will go into DTE command mode when TR goes off. When TR goes
on, if the DSU does not receive a command in the number of seconds set in S40,
the DSU will go into data mode.

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Chapter 6. Configuring DTE Options

SR Options
The SR OPTIONS menu is used to select the operating mode for the
data set ready (SR) lead. From the DTE options menu, press Shift +
A to activate the SR OPTIONS submenu; then press ENTER to select.
The factory default setting is OFF TEST ONLY (see Figure 6-11).
1= NETWORK OPT.
1= LOCAL

1= DTE RATE
2= DTE OPTIONS

2= CONNECTOR TYPE
3= DATA FORMAT

3=CONFIG

4= DTE CMD OPTION
5= TRANSMIT CLOCK
2= REMOTE ENTER ADDRESS

3= TEST OPTIONS

6= CS OPTIONS

4= DIAL OPTIONS

7= ANTI-STREAM

1= FORCED ON

5= MANUAL COM.

8= CD OPTIONS

2= OFF OOS ONLY

9= TR OPTIONS

3= OFF LOCD ONLY

A= SR OPTIONS

4= OFF TEST ONLY

B= AUXILIARY PORT

5= OFF TEST +OOS
6= OFF TEST + LOCD

Figure 6-11. Setting SR Options
Table 6-10 shows the AT commands for setting SR OPTIONS.
Table 6-10. SR Options AT Commands
Front Panel

AT Command

Description

1=FORCED ON

&S0

Always on

2=OFF OOS ONLY

&S1

Off when network Out Of Service
(OOS)

3=OFF LOCD ONLY

&S3

Off 5 seconds after disconnect (SW56
only)

4=OFF TEST ONLY

&S0_C0

Off when unit is in test

5=OFF TEST +OOS

&S1_C0

Off in test or OOS

6=OFF TEST +LOCD &S5

61202011L1-1

Off 5 seconds after disconnect or test

DSU III AR User Manual

6-15

Chapter 6. Configuring DTE Options

Auxiliary Port
The AUXILIARY PORT option is used to select the operating speed for
the secondary channel if the secondary channel option was selected
during setup of the NETWORK OPTIONS (see Figure 6-12). From the
DTE options menu, press Shift + B to activate the AUXILIARY PORT
submenu and press Enter to select. The factory default is OFF.
The AUXILIARY PORT has an internal 256 byte buffer. If the
secondary channel speed is higher than the throughput in the
network, CTS flow control is activated. If the secondary DTE does
not respond to CTS flow control, care should be taken to prevent
the AUXILIARY PORT internal buffer from overflowing. The
AUXILIARY PORT option may also be used to provide VT-100 menu
access through the EIA-232 interface. For more details on this
option, refer to VT-100 Connection on page 4-5.
1= NETWORK OPT.
1= LOCAL

1= DTE RATE
2= DTE OPTIONS

3= CONFIG
2= REMOTE ENTER ADDRESS

2= CONNECTOR TYPE
3= DATA FORMAT

1= 1.2K AT_CMD

4= DTE CMD OPTION

2= 75 SEC

5= TRANSMIT CLOCK

3= 150 SEC

6= CS OPTIONS

4= 300 SEC

4= DIAL OPTIONS

7= ANTI-STREAM

5= 600 SEC

5= MANUAL COM.

8=CD OPTIONS

6= 1.2K SEC

3= TEST OPTIONS

9=TR OPTIONS

7= 2.4K SEC

A= SR OPTIONS

8= OFF

B= AUXILIARY PORT

9= 300 CONTROL
A= 1.2K CONTROL
B= 2.4K CONTROL
C= 9.6K CONTROL

Figure 6-12. Setting the Secondary Rate

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Chapter 6. Configuring DTE Options

Table 6-11 shows the equivalent AT commands for setting the
secondary rate option. Network throughput is shown in Table 6-12.
Table 6-11. Auxiliary Port AT Commands
Front Panel

AT Command Description

1=OFF

_Y0

No secondary channel selected

2=75

_Y1

Secondary channel rate: 75 bps

3=150

_Y2

Secondary channel rate 150 bps

4=300

_Y3

Secondary channel rate: 300 bps

5=600

_Y4

Secondary channel rate 600 bps

6=1.2K

_Y5

Secondary channel rate 1200 bps

7=2.4K

_Y6

Secondary channel rate: 2400 bps

Table 6-12. DSU III AR Network Throughput
Loop Rate

61202011L1-1

Secondary Channel Throughput

2.4k

4.8k

156

9.6k

312

19.2k

627

38.4k

1.25k

56k No Scrambler

1.83k

56k Scrambler

2.4k

DSU III AR User Manual

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Chapter 6. Configuring DTE Options

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Chapter 7

Configuring Test Options

TEST OPTIONS
The TEST OPTIONS menu enables or disables different test modes
and specifies the maximum test time allowed.

Test Time-out
The TEST TIME-OUT option sets the length of time a DSU III AR
remains in a test mode before automatically returning to the data
mode. Enter the time-out from 0 to 255 seconds. The factory default
setting is off (0). Figure 7-1 shows the menu path used to access
TEST TIME-OUT.
1= NETWORK OPT.
1= LOCAL

2= DTE OPTIONS

3=CONFIG
2= REMOTE

ENTER ADDRESS

3= TEST OPTIONS

1= TEST TIMEOUT

ENTER TIME-OUT

4= DIAL OPTIONS

2= RDL/EN /DIS

(0=OFF: 00 SEC)

5= MANUAL

3= EIA LLB /EN /DIS
4= EIA RLB /EN /DIS

Figure 7-1. Setting Test Time-out Option

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7-1

Chapter 7. Configuring Test Options

Table 7-1 shows the equivalent AT commands for setting the
TEST TIME-OUT.
Table 7-1. Test Timeout AT Commands
Front Panel

AT Command

Description

ENTER TIMEOUT

S18=x

Specify 0 - 255 seconds test time-out

Remote Digital Loopback
The REMOTE DIGITAL LOOPBACK (RDL) option specifies whether the
DSU III AR responds to an RDL request from the far end of the
circuit. The factory default setting is RDL ACCEPTED. Figure 7-2
shows the menu path used to access this option.
1= NETWORK OPT.
1= LOCAL
3=CONFIG
2= REMOTE ENTER ADDRESS

2= DTS OPTIONS

1= TEST TIMEOUT

1= RDL IGNORED

3= TEST OPTIONS

2= RDL/EN /DIS

2= RDL ACCEPTED

4= DIAL OPTIONS

3= EIA LLB /EN /DIS

5= MANUAL

4= EIA RLB /EN /DIS

Figure 7-2. Remote Digital Loopback

Table 7-2 shows the equivalent AT commands for setting the
RDL OPTION.
Table 7-2. Remote Digital Loopback AT Commands
Front Panel

AT Command

Description

1=RDL IGNORED

&T5

RDL request from remote DSU ignored

2=RDL ACCEPTED &T4

7-2

RDL request accepted

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Chapter 7. Configuring Test Options

EIA Local Loopback
The EIA LLB (Electronics Industries Association Local Loopback)
option specifies whether the DSU III AR responds to the LLB input
from the DTE. The factory default setting is DISABLED. Figure 7-3
shows the menu path used to access the EIA LLB option.
1= NETWORK OPT.
1= LOCAL
2= DTE OPTIONS

1= TEST TIMEOUT

3= TEST OPTIONS

3= EIA LLB /EN /DIS

1= DISABLED

4= DIAL OPTIONS

4= EIA RLB /EN /DIS

2= ENABED

2= RDL/EN /DIS
3=CONFIG
2= REMOTE ENTER ADDRESS

5= MANUAL

Figure 7-3. EIA Local Loopback Options
Table 7-3 shows the equivalent AT commands for setting the
EIA LLB options.
Table 7-3. EIA Local Loopback AT Commands

61202011L1-1

Front Panel

AT Command

Description

1=DISABLED

_A0

EIA LLB disabled

2=ENABLED

_A1

EIA LLB enabled

DSU III AR User Manual

7-3

Chapter 7. Configuring Test Options

EIA Remote Loopback
The EIA RLB (Electronics Industries Association Remote
Loopback) option specifies whether the DSU III AR responds to the
RLB input from the DTE. The factory default setting is DISABLED.
Figure 7-4 shows the menu path for the EIA RLB options.
1= NETWORK OPT.
1= LOCAL

1= TEST TIMEOUT

3=CONFIG

2= DTS OPTIONS

2= RDL/EN /DIS
3= EIA LLB /EN /DIS

2= REMOTE ENTER ADDRESS

3= TEST OPTIONS

4= EIA RLB /EN /DIS

4= DIAL OPTIONS

1= DISABLED
2= ENABED

5= MANUAL

Figure 7-4. EIA Remote Loopback Options
Table 7-4 shows the equivalent AT commands for setting the EIA
RLB options.
Table 7-4. EIA Remote Loopback AT Commands

7-4

Front Panel

AT Command

Description

1=DISABLED

_R0

EIA RLB disabled

2=ENABLED

_R1

EIA RLB enabled

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Chapter 8

Configuring Dial Options

DIAL OPTIONS
The DIAL OPTIONS menu stores up to ten phone numbers and
defines the AUTO ANSWER operation of the DSU III AR when it is
configured for Switched 56 operation.

Phone Number
The DSU III AR stores up to 10 numbers of 36 digits each. Edit a
phone number by reentering the entire number. This process
overwrites the previously stored number. Figure 8-1 shows the
menu path used to access the PHONE NUMBER option.
1=NETWORK
1=LOCAL

2= DTE OPTIONS
3=TEST OPTIONS

3=CONFIG

STORED NUMBER
2=REMOTE ENTER
ADDRESS

4=DIAL OPTIONS

1=PHONE

TO EDIT: (1-10)

NNNNNNN

2=AUTO ANSWER

Figure 8-1. Editing Stored Phone Numbers

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DSU III AR User Manual

8-1

Chapter 8. Configuring Dial Options

Table 8-1 shows the AT Command for storing phone numbers.
Table 8-1. AT Command for Storing Phone Numbers
AT Command

Description

&Zn=

Store Phone Number

Auto Answer
The AUTO ANSWER option is used to specify how incoming calls are
to be answered. If ENABLED, incoming calls are automatically
answered by the DSU III AR. If DISABLED, an incoming call can be
answered manually by an AT or V.25 command from the DTE, or
by raising TR from the DTE. Figure 8-2 shows the menu path used
to enable or disable this option.
1= NETWORK
1= LOCAL

2= DTE OPTIONS
3= TEST OPTIONS

3=CONFIG
1= PHONE
2= REMOTE

ENTER ADDRESS

4= DIAL OPTIONS 2= AUTO ANSWER

1= DISABLED
2= ENABLED

Figure 8-2. Enabling/Disabling the Auto Answer Function

Table 8-2 shows the AT Commands available for the AUTO ANSWER
option.
Table 8-2. AT Commands for Auto Answer
Front Panel

8-2

AT Command Description

1=DISABLED _J0

Auto Answer disabled

2=ENABLED

Auto Answer enabled

_J1

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Chapter 9

Manual Command

MANUAL COMMAND
The MANUAL COMMAND option is a shortcut method for entering
configuration and control commands for the DSU III AR.
The first display prompts the user to enter the command number.
COMMAND:00
Figure 9-1 shows the menu path for MANUAL COMMAND.
The available manual commands are listed in Table 9-1 on page 9-3.

1= NETWORK OPT.
1= LOCAL

2= DTE OPTIONS
3= TEST OPTIONS
4= DIAL OPTIONS

3=CONFIG

COMMAND: 00
2= REMOTE

ENTER ADDRESS

5= MANUAL COMMAND

COMMAND: 00

VALUE: 00

Figure 9-1. Menu Path for Manual Command

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DSU III AR User Manual

9-1

Chapter 9. Manual Command

Using the Front Panel to Enter a Manual Command
When using the front panel, perform the following steps to enter a
manual command.
Step

Action

Explanation

Use the number keys to enter When the command number is enthe hexadecimal command
tered, the display shows both the
number.
command number and the present
value or setting for the command.
Press Enter to complete.

The command value can be
edited or reissued with the existing value.
COMMAND: XX
VALUE: 00

9-2

Use the number keys to enter
the hexadecimal value.

Press Enter to complete.

The system briefly displays
COMMAND ACCEPTED and returns
to the active menu.

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Chapter 9. Manual Command

Table 9-1. Manual Commands
Command Description
AT Command Echo
Disable
Enable
AT Result code
Enable
Disable
AT Long or Short code
Short form
Long form
AT Escape Character
AT CR Character
AT LF Character
AT BS Character
AT Escape Char. Timer
Abort Call Timer
DTR Recognize Delay (x 2.5ms)
DTR Initiated Command Time-out (seconds)
Load Factory Opt.
Option Set #1
Option Set #2
Option Set #3
Option Set #4
Store User Profile
Save to Profile 0
Save to Profile 1
Select User Profile
Power Up Profile 0
Power Up Profile 1
Network Address Lock
Network Addr. Unlock
Network Addr. Lock

61202011L1-1

DSU III AR User Manual

Command

Value

82
82

00
01

85
85

00
01

86
86
2
3
4
5
0C
7
19
28

00 to FF
00 to FF
00 to FF
00 to FF
00 to FF
00 to FF
00 to FF
00 to FF
00 to FF
00 to FF

8A
8A
8A
8A

00
01
02
03

91
91

00
01

93
93

00
01

C3
C3

00
01

9-3

Chapter 9. Manual Command

9-4

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Chapter 10

Dial Selection

DIAL OPTIONS
The DIAL selection available in the MAIN menu (DIAL) includes
options for manual dialing, redialing, and dialing stored numbers.
The DIAL selection is available for use only if AT&T/MCI SW56 or
US SPRINT SW56 is the selected NETWORK TYPE. See Network Type
on page 5-5 in Chapter 5.
Figure 10-1 below shows the menu path used to access these
options.

1= DIAL STORED # Select Stored Number 1-A
4=DIAL

2= ENTER DIAL #

NNNNNNN

3= REDAIL LAST #
Figure 10-1. Dial Options Menu

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DSU III AR User Manual

10-1

Chapter 10. Dial Selection

Dial Stored Number
This option allows a stored number to be dialed. The numbers are
stored within the CONFIG selection.
Figure 10-2 below shows the CONFIG menu path used to access the
dial options and store phone numbers.
See Chapter 8 Configuring Dial Options on page 8-1 for more
information.

1= NETWORK TYPE
1= LOCAL

2= DTE OPTIONS
3= TEST OPTIONS
STORED NUMBER

3= CONFIG

4= DIAL OPTIONS
2= REMOTE ENTER
ADDRESS

1= PHONE NO.

EDIT: (1-10)

NNNNNNN

2= AUTO ANSWER
5= MANUAL

Figure 10-2. Path to Storing Numbers Option

Enter Dial Number
This option allows you to enter a phone number of up to 36 digits
for the DSU III AR to dial.

Redial Last Number
Selecting this option redials the last phone number entered.

10-2

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Chapter 11

Testing and Troubleshooting

TEST OVERVIEW
The DSU III AR performs a variety of diagnostic functions that
isolate portions of the circuit to identify the problem source. Tests
may be initiated and terminated from the front panel or the DTE
interface. In asynchronous mode, AT commands can control the
testing from the DTE interface. For synchronous operation, V.25 bis
commands can provide test control.
The unit also responds to standard DDS network tests initiated
from telco test centers. In addition, it can run several tests such as
local and remote loopbacks to aid in problem isolation. See Figure
11-1.

DTE

LOCAL
DSU/CSU

REMOTE
DSU/CSU
TELCO

DTE

Figure 11-1. Normal Operation Before Initiating Loopback Test

All diagnostic tests disrupt data flow.

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DSU III AR User Manual

11-1

Chapter 11. Testing and Troubleshooting

Initiating a Test
To initiate tests, perform the following steps:
Step

Action

To select TEST from the main menu, press 2; then press
Enter.

Specify LOCAL, REMOTE, or AR testing by selecting the
corresponding number; then press Enter.

Use the up and down arrows to view test options.

Select a test from the available options by pressing the
corresponding number and then Enter.

The example in Figure 11-2 shows the menu path for initiating a
local DTE and Loop test.
1=DTE & LOOP (LL)
2=LOOP ONLY (RT)
1=LOCAL UNIT

3=DTE ONLY
4=DTE WITH TP
5=TEST PATTERN

2=TEST

6=SELF TEST

2=REMOTE UNIT

ENTER TEST UNIT
ADDRESS: 0
Figure 11-2. Initiating a Test

Once a test is initiated PLEASE WAIT displays briefly and is
followed by the status screen.

11-2

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Chapter 11. Testing and Troubleshooting

Test Status Display
The TEST STATUS display appears automatically during a test. The
TEST STATUS display is similar to the status screen described in
Chapter 12, Viewing Status Information on page 12-1 with additional
prompts for the type of test and the number of errors (for tests with
a test pattern).
Figure 11-3 shows an example of a TEST STATUS DISPLAY for a DTE
test with a test pattern. Figure 11-4 on page 11-4 shows the
complete test menu.
DTE WITH TEST PATTERN
TST ERR = 00

While this menu is on the display:
Press 1 to clear errors.
Press 2 to inject an error.

LOOP 56K
DTE 56K SYNC
TR SR LLB RLB
OFF OFF OFF OFF

Use the up and down arrows to
display other status screens.

UNIT IN TEST
LOOP IS NORMAL
Figure 11-3. Sample Test Status Displays

Exiting a Test
During a test, press the Quick key to access the EXIT TEST/DISPLAY
STATUS menu or press Cancel to return to the Main menu. The EXIT
TEST/DISPLAY STATUS menu provides the following options, which
are available only after a test has been initiated:
Exit Test

Exits the current test and returns to the Main
menu.

Display Status Reenters test display.

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DSU III AR User Manual

11-3

Chapter 11. Testing and Troubleshooting

1=DTE & LOOP (LL) STATUS DISPLAY

1=EXIT TEST
2=DISPLAY STATUS

2=LOOP ONLY (RT) STATUS DISPLAY

1=EXIT TEST
2=DISPLAY STATUS

3=DTE ONLY

STATUS DISPLAY

1=LOCAL UNIT

1=EXIT TEST
2=DISPLAY STATUS

1=2047 PATTERN
4=DTE WITH TP
TEST

2=511 PATTERN
3=STRESS PTRN #1

1=EXIT TEST
STATUS DISPLAY

2=DISPLAY STATUS

4=STRESS PTRN #2
5=STRESS PTRN #3
6=STRESS PTRN #4
1=2047 PATTERN
2=511 PATTERN
3=STRESS PTRN #1
5=TEST PATTERN 4=STRESS PTRN #2

1=EXIT TEST
STATUS DISPLAY

2=DISPLAY STATUS

5=STRESS PTRN #3
6=STRESS PTRN #4

6=SELF TEST

STATUS DISPLAY
1=2047 PATTERN
2=511 PATTERN

1=EXIT TEST
STATUS DISPLAY

2=DISPLAY STATUS

2=REMOTE UNIT ENTER TEST UNIT 3=STRESS PTRN #1
ADDRESS: 0

4=STRESS PTRN #2
5=STRESS PTRN #3
6=STRESS PTRN #4
7=DATA FROM DTE

Figure 11-4. Complete Test Menu
When the
menus.
11-4

STATUS DISPLAY

is active, press the Quick key to access the EXIT TEST

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Chapter 11. Testing and Troubleshooting

TROUBLESHOOTING
This section is intended to provide a quick and easy means of
diagnosing suspected problems associated with local or remotely
attached ADTRAN DSU/CSUs. Two separate troubleshooting
sections are provided; one focuses on new installs, the other on
existing circuits.

Messages from the DSU/CSU
The DSU III AR displays messages on the LCD display and LEDs
concerning the status of the unit and the local loop. If the Alarm
LED is ON, at least one of the messages shown in Table 11-1 will be
displayed on the LCD.

The STATUS menu must be selected in order for the unit to display status
messages. Press the Quick key to return to the main menu, where STATUS
can be selected.

Table 11-1. Messages from the DSU/CSU
Message

Meaning

Probable Cause

LOOP IS
NORMAL

Good local loop signal being received
from the telco.

OPEN LOOP

Unit not receiving a Bad telco cable from
signal from the telco. the DSU to telco jack
or bad circuit to telco.

Replace telco cable from
DSU to wall jack. If a problem persists, contact telco
provider.

NO RX
SIGNAL

Unit detects sealing
current but no data
signal from telco.

Bad conductor in telco
cable from DSU to telco jack or bad circuit to
telco.

Replace telco cable from
DSU to wall jack. If a problem persists, contact telco
provider.

OOS/OOF
FROM NET

Unit detects an Out of
Service or Out of
Frame condition from
the telco.

Telco is having problems with DDS circuit
or remote unit is turned
off or disconnected.

Check remote unit. Contact
telco service provider. If a
problem persists, contact telco provider.

61202011L1-1

Indicates good local
loop.

Action

DSU III AR User Manual

No action required; unit
properly connected to telco
circuit.

11-5

Chapter 11. Testing and Troubleshooting

Table 11-1. Messages from the DSU/CSU (Continued)
Message

Meaning

Probable Cause

CHECK
TELCO LINE

Transmit/receive pair Telco wall jack wired
reversal detected.
incorrectly.

TEST FROM
TELCO

Telco activated a
loopback to test the
DDS circuit.

Action
Switch wire pairs in wall jack
or contact telco service provider.

Telco is testing circuit. Wait until test is complete or
contact telco service provider.

Troubleshooting New Installs
Before initiating diagnostics on a newly installed unit and/or DDS
circuit and before contacting ADTRAN Technical Support, please
check the items in Table 11-2 to ensure the unit is configured
properly.
After verifying the items listed in Table 11-2 on page 11-7, the unit
should operate properly and display the following:
DATA MODE
LOOP IS NORMAL
If a status message other than DATA MODE LOOP IS NORMAL is
shown, begin performing diagnostics described in the section Test
Sequence for Troubleshooting New Installs or Existing Circuits on page
11-8.

11-6

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Chapter 11. Testing and Troubleshooting

Table 11-2. Troubleshooting New Installs
Configuration Item to
Check

Option Selection

Action

DTE Type

EIA-232 or V.35

Loop Rate

Auto, 2.4 to 64 kbps Select the DDS loop rate of the
DDS circuit from the configuration
menu.

Data Format

Async or Sync

Select the type of data to be used
from the configuration menu.

DTE Cable

N/A

Verify DTE cable connection to
the proper DTE connector on the
DSU/CSU.

Telco Cable

N/A

Verify the telco cable is securely
connected to the DSU/CSU and
wall jack.

Power the unit Off and
then On.

N/A

Verify the unit passes self test
during power-up (displayed on
the LCD).

61202011L1-1

Select the type of DTE interface
option to connect to the DSU/
CSU from the configuration
menu.

DSU III AR User Manual

11-7

Chapter 11. Testing and Troubleshooting

Test Sequence for Troubleshooting New Installs or Existing Circuits
If your DSU...

Do this...

seems to be having problems

Perform a Self Test to determine if the unit is
operational

is receiving excessive data errors

Perform a DTE with Test Pattern requiring retransmission to determine if the unit's internal
transmitter and receiver is operating error free

is receiving excessive errors
requiring retransmission of data
and the remote unit is error free

Perform a Remote Test to verify the connection
between the local and remote unit is error free.
Run the test using all available test patterns

If an external BERT tester is available, these additional tests may be performed: DTE & Loop Test, DTE Only Test, and Loop Only Test.

If the unit fails any of these tests or the problem has not been
determined, contact ADTRAN Technical Support (see page xi in
the front section of this manual).
The DSU III AR unit diagnostics tests can be initiated through AT
Commands from the DTE interface. These commands are listed in
Table 11-3 on page 11-9.

11-8

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Chapter 11. Testing and Troubleshooting

Table 11-3. AT Commands

61202011L1-1

Command

Title

Default

Re-execute Command

none

ATA

Answer

none

ATDn

Dial Number

none

ATE

Echo Command

ATH

Hang Up Call

none

ATO

Go Online

none

ATQn

Result Code Display

ATSn?

Read S-Register

none

ATSn=x

Write to S-Register

none

ATVn

Result Code From

ATZ

Reset

none

AT&Cn

DCD Option

AT&Dn

DTR Option

AT&Fn

Restore Factory Options

none

AT&Kn

Flow Control

none

AT&Ln

Network Type

AT&Qn

DTE Data Format

AT&Rn

CS Options

AT&Sn

SR Options

AT&Tn

Test Commands

AT&V

View Current Configuration

none

AT&Wn

Store User Profile

DSU III AR User Manual

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Chapter 11. Testing and Troubleshooting

LOCAL UNIT DIAGNOSTICS
The local DSU III AR can perform six different tests. These tests can
be initiated through AT Commands from the DTE Interface. See
Table 11-4 for a list of the AT Commands.
Table 11-4. Test AT Commands
Front Panel Display AT Command Description
DTE & Loop (LL)

&T10

TD/RD and RX/TX Loopbacks

Loop Only (RT)

&T11

RX/TX Loopback at Network Interface

DTE Only

&T1

TX/RX Loopback at DTE Interface

DTE with TP

&T8

RX/RX Loopback with Test Pattern

Test Pattern

&T9

Transmit/Receive Test Pattern

Self Test

Check Internal Components (Resets
Unit)

Exit Test

&T0

Stops test, returns to data mode

TD = Customer Transmit Data
RD = Customer Receive Data
TX = Network Transmit Data
RX = Network Receive Data
The test patterns shown in Table 11-5 on page 11-11 are available for
the DTE with Test Pattern and Test Pattern tests.

11-10

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Chapter 11. Testing and Troubleshooting

Table 11-5. DTE With Test Pattern Commands
Front Panel

AT
Command

Description

1=2047 PATTERN

_T0&T8

Standard 2047 random data pattern.

2=511 PATTERN

_T1&T8

Standard 511 random data pattern.

3=STRESS PTRN #1 _T2&T8

Stress pattern with alternating high and
low ones densities. Repeated pattern of
100 octets: 1111 1111; followed by 100
octets: 0000 0000.

4=STRESS PTRN #2 _T3&T8

Stress pattern with alternating medium
and low ones densities. Repeated pattern
of 100 octets: 0111 1110; followed by 100
octets: 0000 0000.

5=STRESS PTRN #3 _T4&T8

Stress pattern with medium ones density.
Continuous series of octets: 0011 0010.

6=STRESS PTRN #4 _T5&T8

Stress pattern with low ones density. Continuous series of octets: 0100 0000.

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Chapter 11. Testing and Troubleshooting

DTE and Loop (LL)
Test Description
The DTE & LOOP test splits the DSU III AR into two separate DTE
and loop interface sections and then loops the receive data of each
interface back to its respective transmit data. The DTE & LOOP test
provides a bidirectional loopback at the DSU/CSU.
Figure 11-5 illustrates the loopback points and the signal paths for
this test.

LOCAL
DSU/CSU

DTE

DTE Tx

NET Tx

TELCO
DTE Rx

NET Rx

Figure 11-5. DTE & Loop Test
Test Purpose
The DTE & Loop test is used for the following purposes:

11-12

•

Verify integrity of the DTE interface and cable.

•

Provide a loopback for network tests.

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Chapter 11. Testing and Troubleshooting

Initiating
Follow the menu path outlined in Figure 11-6 to initiate a DTE &
LOOP TEST.
1=DTE & LOOP (LL)
2=LOOP ONLY (RT)
3=DTE ONLY
1=LOCAL UNIT

4=DTE WITH TP
5=TEST PATTERN

2=TEST

6=SELF TEST
2=REMOTE UNIT
Figure 11-6. Initiating a DTE & Loop Test

Interpreting Test Results
A BERT tester must be used to interpret the test results of a DTE &
Loop test because the BERT originates external to the local DSU.

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Chapter 11. Testing and Troubleshooting

Loop Only (RT)
The LOOP ONLY (RT) test allows the loop interface and a major
portion of the DTE interface for the local DSU III AR to be tested
from the remote site over the actual communication circuit.
Figure 11-7 illustrates the loopback point and the signal paths for
this test.

LOCAL
DSU/CSU

DTE
Interface

DTE Tx

NET Tx

TELCO
DTE Rx

NET Rx

Figure 11-7. Loop Only Test
Test Purpose
The LOOP ONLY test is used to provide a loopback for network tests.

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Chapter 11. Testing and Troubleshooting

Initiating
Follow the menu path outlined in Figure 11-8 to initiate a
LOOP ONLY test.
1=DTE & LOOP (LL)
2=LOOP ONLY (RT)
3=DTE ONLY
1=LOCAL UNIT

4=DTE WITH TP
5=TEST PATTERN

2=TEST

6=SELF TEST
2=REMOTE UNIT
Figure 11-8. Initiating a Loop Only Test

Interpreting Test Results
The LOOP ONLY test is used for looping the DDS circuit back to the
telco. No test results are available from the local DSU III AR.

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Chapter 11. Testing and Troubleshooting

DTE Only
The DTE ONLY test provides a method for testing both the DTE
interface drivers and receivers of the local DSU III AR plus its loop
transmitter and receiver. For this test, the loop transmit data is
connected to the loop receive data at a point close to the physical
network interface. This test can be used to verify proper operation
between the local DTE and the local DSU III AR. See Figure 11-9.

When this test is implemented, the far unit receives an OOS/OOF message from the network and enters an alarm state.

LOCAL
DSU/CSU

DTE
TD

DTE Tx

NET Tx

TELCO
RD

DTE Rx

NET Rx

Figure 11-9. DTE Only Test Diagram
Test Purpose
The DTE ONLY test is used for the following purposes:

11-16

•

To verify the integrity of the DTE interface.

•

To verify the integrity of connection between DTE and
DSU III AR.

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Chapter 11. Testing and Troubleshooting

Initiating
Follow the menu path outlined in Figure 11-10 to initiate a
DTE ONLY test.
1=DTE & LOOP (LL)
2=LOOP ONLY (RT)
3=DTE ONLY
1=LOCAL UNIT

4=DTE WITH TP
5=TEST PATTERN

2=TEST

6=SELF TEST
2=REMOTE UNIT
Figure 11-10. Initiating a DTE Only Test

Interpreting Test Results
A BERT tester must be used to interpret the test results of a
DTE ONLY test because the BERT originates external to the local
DSU.

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Chapter 11. Testing and Troubleshooting

DTE With Test Pattern
The DTE with TP (test pattern) test is similar to the DTE ONLY test
described previously except the test pattern is generated in the
DSU using the DSU/CSU internal test pattern generator. This test
can be used to detect deficiencies within the internal drivers and
receivers of the DSU III AR. Figure 11-11 illustrates the loopback
point and the data paths for this test.

LOCAL
DSU/CSU
DTE

Error
Inject

Test Pattern
Generator

DTE Tx

NET Tx

DTE Rx

NET Rx

Error
Clear

Test Pattern
Detector

Figure 11-11. DTE with Test Pattern
Test Purpose
A DTE test using a test pattern is used for the following purposes:

11-18

•

Verify integrity of the DTE interface.

•

Verify integrity of connection between DTE and DSU III AR.

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Chapter 11. Testing and Troubleshooting

Initiating
Follow the menu path outlined in Figure 11-12 to initiate a DTE Test
using a 511 Test Pattern.

1=LOCAL UNIT
2=TEST

1= DTE & LOOP (LL)

1= 2047 PATTERN

2= LOOP ONLY (RT)

2= 511 PATTERN

3= DTE ONLY

3= STRESS PTRN #1

4= DTE WITH TP

4= STRESS PTRN #2

5= TEST PATTERN

5= STRESS PTRN #3

6= SELF TEST

6= STRESS PTRN #4

2=REMOTE UNIT
Figure 11-12. Initiating a DTE Test with Test Pattern
Interpreting Test Results
If the unit is functioning properly, the DSU III AR displays:
DTE WITH TP
TST ERR=0000
The first line of the display indicates the type of test being
performed, while the second line of the display indicates the
number of errors accumulated by the test pattern detector.
If errors occur during this test, the test error count can be reset to
zero by pressing 1 on the keypad.
To verify proper operation of this test, single bit errors can be
injected into the transmitted test pattern by pressing 2. These errors
appear on the TEST ERR display.
Keypad

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Effect

Zeros error counter

Injects single Error

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Chapter 11. Testing and Troubleshooting

Test Pattern
The TEST PATTERN option converts the local DSU III AR into a
BERT tester for the purpose of testing the DDS circuit. When this
test is used, the remote DSU/CSU must be in loopback or
transmitting a test pattern. Figure 11-13 illustrates the data paths
for this mode.

LOCAL
DSU/CSU
Error
Inject

REMOTE
DSU/CSU

Test Pattern
Generator

Error
Inject

Error
Clear

TELCO

Test Pattern
Detector

Test Pattern
Generator

Error
Clear

Test Pattern
Detector

Figure 11-13. Test Pattern Only
Test Purpose
Testing by using a test pattern is used for the following purposes:

11-20

•

Transmits user selected test pattern using an internal test
pattern generator, and compares the received data using
internal test pattern detector to detect whether there are any
errors on the DDS circuit

•

Injects errors and verifies the unit transmits data across the
communication circuit to the remote unit.

•

Helps determine from which direction the circuit is receiving
errors.

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Chapter 11. Testing and Troubleshooting

Initiating
Follow the menu path outlined in Figure 11-14 to initiate a test
using a 511 test pattern.

1= LOCAL UNIT
2=TEST

1= DTE & LOOP (LL)

1= 2047 PATTERN

2= LOOP ONLY (RT)

2= 511 PATTERN

3= DTE ONLY

3= STRESS PTRN #1

4= DTE WITH TP

4= STRESS PTRN #2

5= TEST PATTERN

5= STRESS PTRN #3

6= SELF TEST

6= STRESS PTRN #4

2= REMOTE UNIT
Figure 11-14. Initiating a Test Using a Test Pattern
Interpreting Test Results
If the unit is functioning properly, the display should show the
following:
TEST PATTERN
TST ERR = 0000
The first line of the display indicates the type of test being
performed while the second line of the display indicates the
number of errors accumulated by the test pattern detector.
If errors occur during this test, the test error count can be reset to
zero by pressing 1 on the keypad.
To verify proper operation of this test, single bit errors can be
injected into the transmitted test pattern by pressing 2. These errors
appear on the TEST ERR display.
Keypad

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Effect

Zeros error counter

Injects single Error

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Chapter 11. Testing and Troubleshooting

Self Test
The SELF TEST verifies current operation of the DSU III AR. It can
be performed at any time and is recommended if there is any
question about the DSU's health.
Test Purpose
To determine if the DSU is functioning properly.
Initiating
Follow the menu path outlined in Figure 11-15 to initiate a test
using a test pattern.
1=DTE & LOOP (LL)
2=LOOP ONLY (RT)
3=DTE ONLY
1=LOCAL UNIT

4=DTE WITH TP
5=TEST PATTERN

2=TEST

6=SELF TEST
2=REMOTE UNIT
Figure 11-15. Initiating a Self Test

Interpreting Test Results
Once SELF TEST is activated, the LEDs cycle on and off as the
system runs the self test. A pass or fail status will be displayed on
the LCD along with a checksum indicating the current firmware
revision.

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Chapter 11. Testing and Troubleshooting

REMOTE UNIT DIAGNOSTICS
A remote DSU III AR can perform seven different tests; see Table
11-6.
Table 11-6. Remote Tests and AT Commands
Front
Panel

AT
Command

Description

1=2047 PATTERN

_T0&T7

Standard 2047 random data pattern

2=511 PATTERN

_T1&T7

Standard 511 random data pattern

3=STRESS PTRN #1 _T2&T7

DDS Stress Pattern #1

4=STRESS PTRN #2 _T3&T7

DDS Stress Pattern #2

5=STRESS PTRN #3 _T4&T7

DDS Stress Pattern #3

6=STRESS PTRN #4 _T5&T7

DDS Stress Pattern #4

7=DATA FROM DTE

Data from DTE

&T6

The REMOTE UNIT submenu allows a remotely installed DSU to be
placed into loopback. There are six test patterns to choose from or
DATA FROM THE DTE may be selected. See Figure 11-16.

LOCAL
DSU/CSU
Error
Inject

DTE
Tx
Rx

Test Pattern
Generator

REMOTE
DSU/CSU

DTE Tx

NET Tx

DTE Rx

NET Rx

Error
Clear

TELCO

NET Tx

DTE Tx

NET Rx

DTE Rx

Test Pattern
Detector
Local Unit Initiates Test

Figure 11-16. V.54 RDL with Test Pattern

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Chapter 11. Testing and Troubleshooting

Test Purpose
Test the local DSU, the DDS circuit, and remote DSU.
Initiating
Follow the menu path outlined in Figure 11-17 to place a remote
DSU III AR into loopback.
1= 2047 PATTERN
2= 511 PATTERN
3= STRESS PTRN #1
1= LOCAL UNIT

4= STRESS PTRN #2
5= STRESS PTRN #3

2= TEST

ENTER TEST UNIT
2= REMOTE UNIT ADDRESS: 0

6= STRESS PTRN #4
7= DATA FROM DTE

Figure 11-17. Initiating a Remote Test
After selecting REMOTE UNIT from the menu, the following prompt
is displayed for entering the address for the remote unit:
Enter Test Unit
Address:0
Use the number keys to type the address of the remote DSU; then
press Enter. The test pattern selections are displayed. After a test
pattern is selected, the system briefly displays PLEASE WAIT.
Test Results
If the test is successful the status menu is displayed.
If not, UNABLE TO EXECUTE TEST is displayed.

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Chapter 11. Testing and Troubleshooting

Interpreting Test Results
If the unit is functioning properly, the display should show:
TST ERR = 0000
The keypad buttons can be used to manually inject errors and clear
the error count.
Keypad

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Effect

Zeros error counter

Injects single Error

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Chapter 11. Testing and Troubleshooting

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Chapter 12

Viewing Status Information

STATUS DISPLAY
The STATUS selection displays two lines at a time of the current
operational status of the network and the DTE interfaces.
After 30 seconds of no front panel operation, the DSU III AR
automatically reverts to the status display. Examples of possible
status displays are shown in Figure 12-1.

Screen 1

DATA MODE
LOOP IS NORMAL

Screen 2

LOOP 56K
DTE 56K SYNC

Screen 3

TR SR LLB RLB
ON ON OFF OFF

DSU Operational Status
DDS Network Status
Network Rate
DTE Rate/Mode
DTE Control Leads
Control Lead Status

Figure 12-1. Examples of Status Displays

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Chapter 12. Viewing Status Information

DSU Operational Status
Possible messages include:
Message

Description

DATA MODE

The unit is ready to pass data if network status is
normal.

UNIT IN TEST

The unit is in test. Scroll to next status menu for
test type.

DTE COMMAND MODE The unit is in command mode from the DTE (AT or
V.25 bis).
In SW56 mode the following messages are possible:

12-2

IDLE

The unit is idle, waiting for a call or a dial command.

INCOMING CALL

The unit has detected an incoming call.

DIALING

The unit is dialing a number.

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Chapter 12. Viewing Status Information

DDS Network Status
This line of the display shows the current status of the dedicated
network interface. Possible messages include:
Message

Description

LOOP IS NORMAL

The DSU is connected to the dedicated line. No line
irregularity detected.

OPEN LOOP

The DDS physical connection has been broken.

NO RX SIGNAL

The DSU III detects sealing current but no receive
signal.

CHECK TELCO LINE

The DSU III detects a possible reversal in the Rx
and Tx pairs.

OOS/OOF FROM NET

The DSU III detects an abnormal condition code
from the network.

NO FRAME SYNC

The DSU III cannot sync on the signal from the telco (64k or secondary channel mode only).

TEST FROM TELCO

The DSU III is in a test initiated from the telco.
Scroll to next status menu for test type.

RATE ADAPTING

The DSU III is attempting to determine the loop rate
provided from the telco.

In SW56 mode the following messages are possible:
ANSWERING CALL

The DSU III is answering an incoming call.

NO WINK FROM CO

The DSU III did not see a proper signal from the
network during dialing.

CALL DISCONNECT

The SW56 was terminated.

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Chapter 12. Viewing Status Information

Network Rate
The message displayed on this line of the STATUS display screen
indicates the rate of the service configured for the network.

DTE Rate/Mode
The message displayed on this line of the STATUS display screen
indicates the DTE data rate and format.

DTE Control Leads and Status
Four additional DTE interface leads are displayed with their
current status (on or off) displayed below them. The leads are
identified as follows:
TR

- Data terminal ready

- Data set ready

LLB - Local loopback
RLB - Remote loopback

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Appendix A

Pinouts

Table A-1. RJ-48S Telco Connector Pinouts

61202011L1-1

Name

Description

Transmit Data from DSU to Network-Ring 1

Transmit Data from DSU to Network-Tip 1

3-6

Not Used

Receive Data from Network to DSU-Tip

Receive Data from Network to DSU-Ring

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A-1

Appendix A. Pinouts

Table A-2. Primary EIA-232 Connector Pinouts

A-2

EIA

Description

Protective Ground (PG)

Transmit Data (TD)

Receive Data (RD)

Request to Send (RS)

Clear to Send (CS)

Data Set Ready (SR)

Signal Ground (SG)

Received Line Signal Detector (CD)

+12 Test Point

-12 Test Point

Transmit Clock (TC)

Receive Clock (RC)

Local Loopback (LL)

Data Terminal Ready (TR)

Remote Loopback (RL)

Ring Indicator (RI)

External TX Clock (ETC)

Test Indicator (TI)

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Appendix A. Pinouts

Table A-3. Primary V.35 Connector Pinouts

61202011L1-1

CCITT

Description

101

Protective Ground (PG)

102

Signal Ground (SG)

105

Request to Send (RTS)

106

Clear to Send (CTS)

107

Data Set Ready

109

Received Line Signal Detector (CD)

Data Terminal Ready (DTR)

Ring Indicator

Local Loopback (LL)

Remote Loopback (RL)

104

Received Data (RD-A)

104

Received Data (RD-B)

115

Receiver Signal Element Timing (SCR-A)

115

Receiver Signal Element Timing (SCR-B)

103

Transmitted Data (SD-A)

103

Transmitted Data (SD-B)

114

Transmitter Signal Element Timing (SCT-A)

114

Transmitter Signal Element Timing (SCT-B)

113

External TX Signal Element (SCX-A)

113

External TX Signal Element (SCX-B)

Test Indicator (TI)

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Appendix A. Pinouts

Table A-4. Auxiliary EIA-232 Connector Pinouts

A-4

CCITT

Description

Protective Ground (PG)

Transmit Data (TD)

Receive Data (RD)

Request to Send (RS)

Clear to Send (CS)

Data Set Ready (SR) On all the time.

Signal Ground (SG)

Received Line Signal Detector (CD) On all
the time.

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Appendix B

AT Commands
This Appendix lists all the AT Commands available for the DSU III
AR.

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Appendix B. AT Commands

Table B-1. AT Commands

B-2

Command

Title

Default

Re-execute Command

none

ATA

Answer

none

ATDn

Dial Number

none

ATE

Echo Command

ATH

Hang Up Call

none

ATO

Go Online

none

ATQn

Result Code Display

ATSn?

Read S-Register

none

ATSn=x

Write to S-Register

none

ATVn

Result Code From

ATZ

Reset

none

AT&Cn

DCD Option

AT&Dn

DTR Option

AT&Fn

Restore Factory Options

none

AT&Kn

Flow Control

none

AT&Ln

Network Type

AT&Qn

DTE Data Format

AT&Rn

CS Options

AT&Sn

SR Options

AT&Tn

Test Commands

AT&V

View Current Configuration

none

AT&Wn

Store User Profile

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Appendix B. AT Commands

Table B-2. Loop Rate Commands
Front Panel

AT Command

AUTO

%B0

2.4K with no secondary channel

%B1

4.8K with no secondary channel

%B2

9.6K with no secondary channel

%B3

19.2K with no secondary channel

%B4

38.4K with no secondary channel

%B5

56K with no secondary channel

%B6

64K clear channel

%B7

2.4K with secondary channel

%B9

4.8K with secondary channel

%B10

9.6K with secondary channel

%B11

19.2K with secondary channel

%B12

38.4K with secondary channel

%B13

56K with secondary channel

%B14

Table B-3. Network Address Command
Front Panel
XX (Decimal)

AT Command

Description

_N=xx

Assigns a 2 digit Network Address

Table B-4. Remote Configuration Commands
Front Panel

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AT Command

Description

1=DISABLE

&P4

Disable Remote Configuration

2=ENABLE

&P5

Enable Remote Configuration

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Appendix B. AT Commands

Table B-5. Network Type Commands
Front Panel

AT Command Description

1=DEDICATED

&L0

Any 4-wire DDS Network

2=AT&T/MCI

&L1

AT&T/MCI Switched 56 Service

3=US SPRINT

&L2

US SPRINT Switched 56 Service

Table B-6. Clock Source Commands
Front Panel

AT Command Description

1=MASTER

_X0

DSU is the master timing source

2=FROM NETWORK

_X1

Network RX Signal is timing source

Table B-7. DTE Rate AT Commands

B-4

Front Panel

AT Command Description

1=DTE 2.4K

%K3

DTE rate 2.4K sync and async

2=DTE 4.8K

%K4

DTE rate 4.8K sync and async

3=DTE 9.6K

%K5

DTE rate 9.6K sync and async

4=DTE 19.2K

%K6

DTE rate 19.2K sync and async

5=DTE 38.4K

%K7

DTE rate 38.4K sync and async

6=DTE 56K/57.6K

%K8

DTE rate 56K sync or 57.6 async

7=SAME AS LOOP

%K9

DTE rate same as loop speed

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Appendix B. AT Commands

Table B-8. Scrambler On/Off AT Commands
Front Panel

AT Command Description

1=SCRAMBLER OFF _F0

DTE data scrambler disabled

2=SCRAMBLER ON

_F1

DTE data scrambler enabled

3=DATA INVERT

_F2

DTE data invert enabled (56 kbps secondary channel Loop Rate only). LBE
codes from DTE suppressed (64 kbps
only).

Table B-9. Data Format Commands
Front Panel

AT Command Description

1=ASYNCHRONOUS

&Q0

Always asynchronous

2=SYNCHRONOUS

&Q2

Always synchronous

For asynchronous options, select the length of the data bytes.
1=ASYNC 9 BITS

N/A

9 bits including start, stop, parity

2=ASYNC 10 BITS

N/A

10 bits including start, stop, parity

3=ASYNC 11 BITS

N/A

11 bits including start, stop, parity

Table B-10. Transmit Clock AT Commands
Front Panel

AT Command

Description

1=NORMAL

&X0

TX clock from DSU selected

2=EXTERNAL

&X1

ETC clock from DTE selected

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Appendix B. AT Commands

Table B-11. CS Options AT Commands
Front Panel

AT Command

Description

1=FORCED ON

&R0

CS always on.

2=FOLLOWS RS

&R1

CS on with RS after delay; off when RS
or if DSU cannot pass data.

3=FOLLOWS CD

&R2

CS off when CD goes off or if DSU cannot pass data.

4=FOLLOWS RS+CD

&R3

CS follows RS after delay and also off if
CD off. If CD goes off after RS is on,
DSU III AR will turn off CS but continue
to pass data until RS goes off. CS also
off if DSU cannot pass data.

5=OFF WITH LOCD

&R4

Off 5 sec after LOCD. Valid only in SW56
mode. CS is forced on but will turn off for
5 seconds after a call is disconnected.

For RS options, select the RS to CS delay length.
1=CS DELAY SHORT

_D0

Short Delay from RS to CS selected.

2=CS DELAY LONG

_D1

Long Delay from RS to CS selected.

Table B-12. Anti-Stream AT Commands

B-6

Front Panel

AT Command Description

1=TIMER OFF

%T0

Anti-stream timer disabled

2=TIME 10 SEC.

%T1

Time-out equal 10 seconds

3=TIME 30 SEC.

%T2

Time-out equal 30 seconds

4=TIME 60 SEC.

%T3

Time-out equal 60 seconds

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Appendix B. AT Commands

Table B-13. CD Options AT Commands
Front Panel

AT Command

Description

1=FORCED ON

&C0

On all the time.

2=NORMAL

&C1

On only when data present on loop.

3=OFF WITH LOCD

&C2

On except after disconnect in Switched
56 application.

Table B-14. TR Options AT Commands
Front Panel

AT Command

Description

1=IGNORE

&D0

Ignore the TR input.

2=IDLE WHEN OFF

&D2

See the following Note.

3=OFF>ON DIAL #1

&D3

Dial Stored #1: TR goes off to on
(SW56 only).

4=OFF>ON DIAL #2

&D4

Dial Stored #2: TR goes off to on
(SW56 only).

Table B-15. SR Options AT Commands
Front Panel

AT Command

Description

1=FORCED ON

&S0

Always on.

2=OFF OOS ONLY

&S1

Off when network Out Of Service
(OOS).

3=OFF LOCD ONLY

&S3

Off 5 seconds after disconnect (SW56
only).

4=OFF TEST ONLY

&S0_C0

Off when unit is in test.

5=OFF TEST +OOS

&S1_C0

Off in test or OOS.

6=OFF TEST +LOCD &S5

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Off 5 seconds after disconnect or test.

DSU III AR User Manual

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Appendix B. AT Commands

Table B-16. Secondary Rate AT Commands
Front Panel

AT Command Description

1=OFF

_Y0

No secondary channel selected

2=75

_Y1

Secondary channel rate: 75 bps

3=150

_Y2

Secondary channel rate 150 bps

4=300

_Y3

Secondary channel rate: 300 bps

5=600

_Y4

Secondary channel rate 600 bps

6=1.2K

_Y5

Secondary channel rate 1200 bps

7=2.4K

_Y6

Secondary channel rate: 2400 bps

Table B-17. Test Time-out AT Commands
Front Panel

AT Command

Description

ENTER TIMEOUT

S18=x

Specify 0 - 255 seconds test time-out

Table B-18. Remote Digital Loopback AT Commands
Front Panel

AT Command

Description

1=RDL IGNORED

&T5

RDL request from remote DSU ignored

2=RDL ACCEPTED &T4

B-8

RDL request accepted

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Appendix B. AT Commands

Table B-19. EIA Local Loopback AT Commands
Front Panel

AT Command Description

1=DISABLED

_A0

EIA LLB disabled

2=ENABLED

_A1

EIA LLB enabled

Table B-20. EIA Remote Loopback AT Commands
Front Panel

AT Command Description

1=DISABLED

_R0

EIA RLB disabled

2=ENABLED

_R1

EIA RLB enabled

Table B-21. AT Command for Storing Phone Numbers
AT Command

Description

&Zn=

Store Phone Number

Table B-22. AT Commands for Auto Answer

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Front Panel

AT Command Description

1=DISABLED

_J0

Auto Answer disabled

2=ENABLED

_J1

Auto Answer enabled

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Appendix B. AT Commands

Table B-23. Test AT Commands
Front Panel Display AT Command Description
DTE & Loop (LL)

&T10

TD/RD and RX/TX Loopbacks

Loop Only (RT)

&T11

RX/TX Loopback at Network Interface

DTE Only

&T1

TX/RX Loopback at DTE Interface

DTE with TP

&T8

RX/RX Loopback with Test Pattern

Test Pattern

&T9

Transmit/Receive Test Pattern

Self Test

Check Internal Components (Resets
Unit)

Exit Test

&T0

Stops test, returns to data mode

TD = Customer Transmit Data
RD = Customer Receive Data
TX = Network Transmit Data
RX = Network Receive Data

B-10

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Appendix B. AT Commands

Table B-24. DTE With Test Pattern Commands
Front Panel

AT Command Description

1=2047 PATTERN

_T0&T8

Standard 2047 random data pattern.

2=511 PATTERN

_T1&T8

Standard 511 random data pattern.

3=STRESS PTRN #1

_T2&T8

Stress pattern with alternating high and
low ones densities. Repeated pattern of
100 octets: 1111 1111; followed by 100
octets: 0000 0000.

4=STRESS PTRN #2

_T3&T8

Stress pattern with alternating medium
and low ones densities. Repeated pattern
of 100 octets: 0111 1110; followed by 100
octets: 0000 0000.

5=STRESS PTRN #3

_T4&T8

Stress pattern with medium ones density.
Continuous series of octets: 0011 0010.

6=STRESS PTRN #4

_T5&T8

Stress pattern with low ones density.
Continuous series of octets: 0100 0000.

Table B-25. Remote Tests and AT Commands
Front Panel

AT Command Description

1=2047 PATTERN

_T0&T7

Standard 2047 random data pattern

2=511 PATTERN

_T1&T7

Standard 511 random data pattern

3=STRESS PTRN #1

_T2&T7

DDS Stress Pattern #1

4=STRESS PTRN #2

_T3&T7

DDS Stress Pattern #2

5=STRESS PTRN #3

_T4&T7

DDS Stress Pattern #3

6=STRESS PTRN #4

_T5&T7

DDS Stress Pattern #4

7=DATA FROM DTE

&T6

Data from DTE

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Appendix B. AT Commands

B-12

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Appendix C

Default Configuration Profiles

DEFAULT CONFIGURATION PROFILES
The DSU III AR contains four different user profiles (Table C-1) or
sets of configurations options stored in read-only memory (see
Table C-2 on page C-2). The unit is shipped from the factory with
profile 1 loaded into the nonvolatile configuration memory. See
Chapter 2, Installation on page 2-1 and Chapter 9, Manual Command
on page 9-1 for more information.
Table C-1. User Profiles

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User Profile

Description

Profile 1 is configured for a 56 kbps, synchronous,
point-to-point or dial up operation with a V.35 connector.

Use profile 2 for a 56 kbps, synchronous, point-topoint or dial up operation with an EIA-232 connector.

Use profile 3 for a SW56, asynchronous operation
with CS and CD forced on.

Use profile 4 for a SW56 operation with DTR idle
when off.

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Appendix C. Default Configuration Profiles

Table C-2. Default Configuration Profiles
Profile Numbers
(00) 1

(01) 2

(02) 3

(03) 4

Manual Command
Escape Character

43=2BH

CR Character

13=0DH

LF Character

10=0AH

BS Character

SW56 Abort Call Timer

50=32H

Escape Guard Timer

50=32H

Command Echo

Enable

Result Code

Enable

Long or Short Code

Long

Test Pattern Type

2047

CS Delay

Short

DTR Recog. Delay
(x2.5ms)

DTR Command Time-out 8
(x1 sec)

Front Panel En/Dis

Enable

AT Password Control

Disable

Loop Rate

AUTO

56k

AUTO

Network Address

Remote Conf. En/Dis

Enable

Network Type

Dedicated

AT&T/MCI
SW56

Clock Source

From
Network

Network Options

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Appendix C. Default Configuration Profiles

Table C-2. Default Configuration Profiles (Continued)
Profile Numbers
(00) 1

(01) 2

(02) 3

(03) 4

DTE Options
Remote DSU Address

DTE Rate (56/64k loop)

Same as Loop

Same as Loop Same as Loop Same as Loop

Scrambler Mode

OFF

Connector Type

V.35

EIA232

V.35

DTE Data Format

SYNC

ASYNC

SYNC

DTE Command Options

DIS

Transmit Clock

Normal

CS Options

Follow RS

Forced On

Follow RS

Anti-stream Timer

Timer Off

CD Options

Normal

Forced On

Normal

TR Options

Ignored

Idle When Off

SR Options

Off Test+OOS

OFF

Off

Secondary Channel Rate OFF

Test Options
Test Time-out

Off

RDL En/Dis

RDL Accepted

RDL Accepted RDL Accepted RDL Accepted

EIA Controlled LLB

Disable

EIA Controlled RLB

Disable

Enable

Dial Options
Auto Answer

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Appendix C. Default Configuration Profiles

C-4

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Appendix D

EIA-232 Connector

56/64 KBPS APPLICATION
The EIA-232 connector, shown in Figure D-1, may be used for 56
and 64 kbps applications. Using the External clock option and this
cable should eliminate data errors caused by excessive delays in the
DTE transmit clock receiver and transmit data driver. When
creating this cable at the DTE interface EIA-232 connector, tie
transmit clock lead (TC) to external transmit (ETC) as shown.
DSU III AR

DTE

Pin 15

ETC

Pin 24
EIA-232 Connector

Figure D-1. EIA-232 Connector

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Appendix D. EIA-232 Connector

D-2

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Appendix E

DSU to DSU Tail Circuit

MODEM TAIL CIRCUIT APPLICATION
A DDS Tail Circuit is a serial connection of two DDS circuits as
shown in Figure E-1 on page E-2. The two circuits are joined at the
DTE port interface of each DSU unit. A special tail circuit crossover
cable is required so that transmit line connects to the receive line on
the other DSU as well as the DTR, CTS, RTS, and CD signal lines
get matched appropriately. Figure E-2 on page E-3 details the
crossover cable wiring.
ADTRAN DSU/CSU units will operate in this configuration.

ADTRAN does not recommend the tail circuit mode due to the potential
for clock slippage and data loss when using this configuration. Moreover,
further problems can occur when each DDS circuit is using a different
master clock source and will require additional hardware called a tail circuit buffer to reduce the risk of data overruns and clock slips.

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Appendix E. DSU to DSU Tail Circuit

DDS
NETWORK

DDS
Loop

DTE

DSU

DTE

DSU

DDS
Loop

DDS
NETWORK

Tail circuit crossover cable

Figure E-1. DDS Tail Circuit

E-2

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Appendix E. DSU to DSU Tail Circuit

An EIA-232 DB-25 DSU tail circuit cable diagram for a DSU tail
circuit application is shown in Figure E-2.

Chassis Ground
TXD
RXD
RTS
CTS
DSR
Signal Ground
CD (RLSD)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

RC (SCR)

DTR

ETC (SCR)

P2
Chassis Ground
TXD
RXD
RTS
CTS
DSR
Signal Ground
CD (RLSD)

RC (SCR)

DTR

ETC (SCR)

Figure E-2. Standard EIA-232-D Crossover Cable

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E-3

Appendix E. DSU to DSU Tail Circuit

E-4

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Appendix F

Specifications Summary

SPECIFICATIONS AND FEATURES
This section describes the standard specifications and features
incorporated in the DSU III AR.
Operating Modes
• Dedicated DDS (point-to-point, multipoint)
•

DDSII DDS with secondary channel (point-to-point,
multipoint) Switched 56 (4-wire)

Data Rates
• Dedicated mode service rate: 2.4, 4.8, 9.6, 19.2, 38.4, 56, and 64
kbps
•

Switched mode service rate: 56 kbps

DTE Rates
• DTE rates match service rates
•

DTE-to-loop rate matching in both dedicated and switched
modes

•

Synchronous rates: 2.4, 4.8, 9.6, 19.2, 38.4, 56, and 64 kbps

•

Asynchronous rates: 2.4, 4.8, 9.6, 19.2, 38.4, and 57.6 kbps

FCC Approval
FCC part 15, class A and part 68
DTE Interfaces
Both EIA-232 andV.35 electrical and physical DTE interfaces

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Appendix F. Specifications Summary

Data Buffering
Internal slack buffer
Clocking
• Normal DDS or private network tributary (slaved to network
receive clock)
•

Private network master (internal clock)

•

Private network master (slaved to external DTE clock)

Switched Mode Dialing Options
• Stored number
•

Front panel keypad

•

DTR dialing of stored number

•

In-band AT commands

•

V.25 bis in-band dialing

Diagnostics
• Network: CSU and DSU loopbacks
•

User: Local DTE and loop, remote V.54

•

Test Patterns: 2047, 511, DDS, stress patterns 1 to 4

Line Requirements
• Loop transmission parameters as defined in:
•

AT&T PUB 62310: Dedicated DDS

•

AT&T PUB 41468: Switched 56

•

SPRINT TS 0046: Switched 56

Line Interface
• RJ-48S, 4-wire, full duplex
Receiver Sensitivity
• -45 dB at all rates

F-2

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Appendix F. Specifications Summary

Environment
• Operating Temperature: 0O C to 50O C (32O F to 122O F)
•

Storage Temperature: -20O C to 70O C (-4O F to 158O F)

•

Relative Humidity: Up to 95% non-condensing

Hardware Specifications
• Dimensions: 2.25"H, 8.75"W, 10.25"D

61202011L1-1

•

Weight: 3 lbs

•

Power: 115 VAC, 60 Hz, 8 W

•

MTBF: 439,754 hours

•

CLEI: DDSUJ602AA

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Appendix F. Specifications Summary

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Appendix G

Acronyms/Abbreviations

ACK...................

acknowledgment

ALM ..................

alarm

ANSI .................

American National Standards Institute

AR......................

access rate

ARP ...................

address resolution protocol

async .................

asynchronous

BECN ................

backward explicit congestion notification

BOP ...................

bit oriented protocol

CCITT ...............

Consultive Committee for International Telephony and Telegraphy

CD .....................

carrier detect

CIR ....................

committed information rate

CO .....................

central office

CPE....................

customer premise equipment

CR, C/R .............

command response

CRC ...................

cyclic redundancy check

CS ......................

clear to send

CSU ...................

channel service unit

CTS....................

clear to send

dB.......................

decibel

DBU...................

dial backup

DCD ..................

data carrier detect

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Appendix G. Acronyms/Abbreviations

DCE ...................

data communications equipment

DDS...................

digital data service

DE ......................

discard eligible

DLCI..................

data link connection identifier

DSAP.................

destination service access point

DSR ...................

data set ready

DSU ...................

data service unit

DTE ...................

data terminal equipment

DTR ...................

data terminal ready

EA ......................

extended address

EBCDIC ............

extended binary coded decimal interexchange code

FECN .................

forward explicit congestion notification

FEP.....................

front end processor

FIFO...................

first in first out

FR.......................

frame relay

FRAD ................

frame relay access device

FRF.....................

frame relay forum

FSU ....................

frame relay service unit

GUI ....................

graphical user interface

HDLC ................

high-speed data link control

IA .......................

inactive

IP........................

internet protocol

ISDN .................

integrated services digital network

ITU.....................

International Telecommunications Union

KA......................

keep alive

kbps...................

kilobits per second

LAN ...................

local area network

LED....................

light emitting diode

LI........................

link integrity

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Appendix G. Acronyms/Abbreviations

LLC....................

logical link control

LMI....................

local management interface

LRC ...................

lateral redundancy check

MIB ...................

management information base

ms ......................

millisecond

OCU ..................

office channel unit

OOS...................

out of service

PPP ....................

point-to-point protocol

PU ......................

physical unit

PVC ...................

permanent virtual circuit

RD .....................

receive data

RDL ...................

remote digital loopback

RFC....................

request for comments

RFECN ..............

remote forward explicit congestion notification

RIP.....................

routing information protocol

RMA..................

return material authorization

RNR...................

receiver not ready

RR ......................

receiver ready

RS ......................

request to send; also recommended standard

RTS ....................

request to send

Rx.......................

receive

SAP....................

service access point

SDLC.................

synchronous data link control

SLIP...................

serial line internet protocol

SNA...................

systems network architecture

SNMP ...............

simple network management protocol

SPID ..................

service profile identifier

SR ......................

data set ready

SVC ...................

switched virtual circuit

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Appendix G. Acronyms/Abbreviations

SW56 .................

switched 56

sync....................

synchronous

TD ......................

transmit data

TR ......................

data terminal ready

Tx .......................

transmit

UA......................

unavailable

UNI ....................

user-to-network interface

VRC ...................

vertical redundancy check

WAN..................

wide area network

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Appendix H

Glossary

American National Standards Institute (ANSI)
Devices and proposes recommendations for international communications standards.
asynchronous
A method of data transmission which allows characters to be sent at irregular
intervals by preceding each character with a start bit, followed by a stop bit.
backward explicit congestion notification (BECN)
A bit set by a frame relay network to notify an interface device (DTE) that congestion avoidance procedures should be initiated by the sending device.
bandwidth
The bandwidth determines the rate at which information can be sent through a
channel (the greater the bandwidth, the more information that can be sent in a
given amount of time).
bridge
A device that supports LAN-to-LAN communications. Bridges may be equipped
to provide frame relay support to the LAN devices they serve. A frame relay
capable bridge encapsulates LAN frames in frame relay frames and feeds them
to a frame relay switch for transmission across the network. A frame relay capable bridge also receives frame relay frames from the network, strips the frame
relay frame off each LAN frame, and passes the LAN frame on to the end device.
Bridges are generally used to connect LAN segments to other LAN segments or
to a WAN. They route traffic on the Level 2 LAN protocol (e.g. the Media Access
Control address), which occupies the lower sub-layer of the LAN OSI data link
layer. See also router.

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Appendix H. Glossary

CD
carrier detect. A signal generated by a modem or DSU/CSU. CD indicates the
presence of a carrier signal on a communications link.
channel service unit
CSU. A device used to connect a digital phone line (T1 or Switched 56 line) coming in from the phone company to either a multiplexer, channel bank, or directly
to another device producing a digital signal; for example, a digital PBX, a PC, or
data communications device. A CSU performs certain line-conditioning and
equalization functions, and responds to loopback commands sent from the central office. A CSU regenerates digital signals. It monitors them for problems, and
provides a way of testing the digital circuit.
CIR
committed information rate. Less than or equal to the access rate, the CIR is used
by the service provider for rate enforcement when the network is congested.
When rates exceed the CIR, frames may be discarded.
clocking
An oscillator-generated signal that provides a timing reference for a transmission link. A clock provides signals used in a transmission system to control the
timing of certain functions. The clock has two functions, (1) to generate periodic
signals for synchronization and (2) to provide a time base.
CPE
customer premise equipment. All telecommunications terminal equipment
located on the customer premises, including telephone sets, private branch
exchanges (PBXs), data terminals, and customer-owned coin-operated telephones.
C/R bit
In the Q.921 protocols, a bit that identifies a data-link-layer frame as either a
command or a response.
CRC
cyclic redundancy check. A computational means to ensure the accuracy of
frames transmitted between devices in a frame relay network. The mathematical
function is computed, before the frame is transmitted, at the originating device.
Its numerical value is computed based on the content of the frame. This value is
compared with a recomputed value of the function at the destination device.

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Appendix H. Glossary

CS
See CTS.
CSU
See channel service unit.
CTS
clear to send. A signal on the DTE interface indicating that the DCE is clear to
send data.
DBU
dial backup. Providing a secondary, switched dial service to route data upon primary link failure.
data service unit
DSU. A device designed to transmit and receive digital data on digital transmission facilities.
dB
decibel. A unit of measure of signal strength, usually the relation between a
transmitted signal and a standard signal source.
data communications equipment (DCE)
Device that provides all the functions required for connection to telephone company lines and for converting signals between telephone lines and DTE. Also see
DTE.
DDS
digital data service. A private line digital service, for transmitting data end-toend at speeds of 2.4, 4.8, 9.6, and 56 kbps and in some cases 19.2, 38.4, or 64 kbps.
The systems can use central hub offices for obtaining test access, bridging legs of
multipoint circuits, and cross connecting equipment. DDS is offered on an interLATA basis by AT&T and on an inter-LATA basis by the Bell operating companies.
data link connection identifier (DLCI)
A unique number assigned to a PVC end point in a frame relay network. Identifies a particular PVC endpoint within a user's access channel in a frame relay
network and has local significance only to that channel.

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Appendix H. Glossary

discard eligibility (DE)
A user-set bit indicating that a frame may be discarded in preference to other
frames if congestion occurs, to maintain the committed quality of service within
the network. Frames with the DE bit set are considered Be excess data.
DSU
See data service unit.
DSU loopback
A telco initiated test which loops the DSU back to the telco and is used to test the
DDS circuit as well as the DSU/CSU.
DTE
data terminal equipment. The end-user terminal or computer that plugs into the
termination point (DCE) of a communications circuit. The main difference
between the DCE and the DTE is that pins two and three are reversed.
end device
The ultimate source or destination of data flowing through a frame relay network sometimes referred to as DTE. As a source device, it sends data to an interface device for encapsulation in a frame relay frame. As a destination device, it
receives de-encapsulated data (i.e., the frame relay frame is stripped off, leaving
only the user's data) from the interface device.
encapsulation
A process by which an interface device places an end device's protocol-specific
frames inside a frame rely frame. The network accepts only frames formatted
specifically for frame relay; therefore interface devices acting as interfaces to a
frame relay network must perform encapsulation. See also interface device and
frame-relay-capable interface device.
file server
In the context of frame relay network supporting LAN-to-LAN communications,
a device connecting a series of workstations within a given LAN. The device performs error recover and flow control functions as well as end-to-end acknowledgment of data during data transfer, thereby significantly reducing overhead
within the frame relay network.

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Appendix H. Glossary

forward explicit congestion notification (FECN)
A bit set by a frame relay network to notify an interface device (DTE) that congestion avoidance procedures should be initiated by the receiving device. See
also BECN.
frame check sequence (FCS)
The standard 16-bit cyclic redundancy check used for HDLC and frame relay
frames. The FCS detects bit errors occurring in the bits of the frame between the
opening flag and the FCS, and is only effective in detecting errors in frames no
larger than 4096 octets. See also cyclic redundancy check (CRC).
frame-relay-capable interface device
A communications device that performs encapsulation. Frame-relay-capable
routers and bridges are examples of interface devices used to interface the customer's equipment to frame relay network. See also interface device and encapsulation.
frame relay frame
A variable-length unit of data, in frame-relay format that is transmitted through
a frame relay network as pure data. Contrast with packet.
frame relay network
A telecommunications network based on frame relay technology. Data is multiplexed. Contrast with packet switching network.
gateway
A device which enables information to be exchanged between two dissimilar
systems or networks.
high level data link control (HDLC)
A generic link-level communications protocol developed by the International
Organization for Standardization (ISO). HDLC manages synchronous codetransparent, serial information transfer over a link connection. See also synchronous data link control (SDLC).
host computer
The primary or controlling computer in a multiple computer operation.
in-band
Signaling (dialing, diagnostics, management, configuration, etc.) over the same
channel used for data.

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H-5

Appendix H. Glossary

ingress
Frame relay frames leaving from an access device in a direction toward the
frame relay network.
interface device
Provides the interface between the end device(s) and a frame relay network by
encapsulating the user's native protocol in frame relay frames and sending the
frames across the frame relay backbone. See also encapsulation and frame-relaycapable interface device.
IP
internet protocol. A protocol which provides for transmitting blocks of data
between hosts identified by fixed-length addresses.
ISDN
integrated services digital network. A network architecture that enables end-toend 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.
local area network (LAN)
A privately owned network that offers high-speed communications channels to
connect information processing equipment in a limited geographic area.
MIB
management information base. A database of network management information
used by SNMP.
multi-point
A configuration or topology designed to transmit data between a central site and
a number of remote terminals on the same circuit. Individual terminals will generally be able to transmit to the central site but not to each other.
out-of-band
Signaling that is separated from the channel carrying information (voice, data,
video, etc.). Typically the separation is accomplished by a filter. The signaling
includes dialing and other supervisory signals.

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Appendix H. Glossary

packet
A message containing both control information and data. The control information is used for routing the packet through a network to its final destination.
Contrast with frame relay frame.
packet-switching network
A telecommunications network based on packet-switching technology, wherein
a transmission channel is occupied only for the duration of the transmission of
the packet. Contrast with frame relay network.
parameter
A numerical code that controls an aspect of terminal and/or network operation.
Parameters control such aspects as page size, data transmission speed, and timing options.
permanent virtual circuit (PVC)
A frame relay logical link, whose endpoints and class of service are defined by
network management. Analogous to an X.25 permanent virtual circuit, a PVC
consists of the originating frame relay network element address, originating data
link control identifier, terminating frame relay network element address, and termination data link control identifier. Originating refers to the access interface
form which the PVC is initiated. Terminating refers to the access interface at
which the PVC stops. Many data network customers require a PVC between two
points. Data terminating equipment with a need form continuous communion
use PVCs. See also data link connection identifier (DLCI).
ping
An internet protocol standard that provides loopback on demand for any device
in an IP network. One device "pings" another by sending a loopback request to
the device's IP address.
point-to-point
Type of communications link that connects a single device to another single
device, such as a remote terminal to a host computer.
remote configuration
A feature designed into ADTRAN DSU/CSU products that allow remote DSU/
CSU to be configured from a local DSU/CSU or VT-100 compatible terminal.

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Appendix H. Glossary

router
A device that supports LAN-to-LAN communications. Routers may be
equipped to provide frame relay support to the LAN devices they serve. A
frame-relay-capable router encapsulates LAN frames in a frame relay frames
and feeds those frame relay frames to a frame relay switch for transmission
across the network. A frame-relay-capable router also receives frame relay
frames from the network, strips the frame relay frame off each frame to produce
the original LAN frame, and passes the LAN frame on to the end device. Routers
connect multiple LAN segments to each other or to a WAN. Routers route traffic
on the Level 3 LAN protocol (e.g., the internet protocol address). See also bridge.
sealing current
A designation for a powering situation that consists of a wet loop without span
power.
service
The provision of telecommunications to customers by a common carrier, administration, or private operating agency, using voice, data, and/or video technologies.
SNA
systems network architecture. The IBM protocol group which governs mainframe communication.
SNMP
simple network management protocol. A control and reporting scheme widely
used to manage devices from different vendors. SNMP operates on top of the
Internet protocol.
SPID
service profile IDentifier. A sequence of digits identifying ISDN terminal equipment to the ISDN switch when more than one ISDN set has been attached to the
same central office. The SPID is assigned by the telco when the ISDN line is
installed and normally resembles a phone number.
SR
data set ready. A signal on the EIA-232 interface that indicates if the communications is connected and ready to start handshaking control signals so communications can begin.

H-8

DSU IV ESP User Manual

61204011L1-1

Appendix H. Glossary

statistical multiplexing
Interleaving the data input of two or more devices on a single channel or access
line for transmission through a frame relay network. Interleaving of data is
accomplished using the DLCI.
switched network
The network of dial-up telephone lines using circuit switching to provide communications services to network users.
synchronous
Communications in which the timing is achieved by sharing a single clock. Each
end of the transmission synchronizes itself with the use of clocks and information sent along with the transmitted data.
synchronous data link control (SDLC)
A link-level communications protocol used in an international business
machines (IBM) systems Network Architecture (SNA) network that manages
synchronous, code-transparent, serial information transfer over a link connection. SDLC is a subset of the HDLC protocol developed by ISO.
TELNET
The standard TCP/IP remote login protocol specified in RFC-854.
VT-100
A non-intelligent terminal or terminal emulation mode used for asynchronous
communications. Used to configure the DSU IQ.

61204011L1-1

DSU IV ESP User Manual

H-9

Appendix H. Glossary

H-10

DSU IV ESP User Manual

61204011L1-1

Index
Numerics
56/64 kbps application, D-1

A
ACES help desk, xi
affidavit
for connection of CPE equipment, viii
for requirements for connection to digital services, v
anti-stream option, 6-12
Applications engineering
how to contact, xi
AT commands
clear to send (CS) B-6
data format B-5
data set ready (SR) B-7
scrambler on/off B-5
secondary rate B-8
storing phone numbers B-9
test timeout B-8
transmit clock B-5
AT commands, 4-5
auxiliary EIA-232 2-3
auxiliary port, 6-16

carrier detect options, 6-13
clear to send (CS)
AT commands B-6
clear to send options menu, 6-10
clock source 5-6
clock source commands, B-4
clocking
specifications, F-2
configuration 2-4
dial options, 8-1
DTE options 6-1
local 4-2
network options 5-1
test options 7-1
configuration local (CNL), 4-10
configuration menu, 3-2
configuration methods, 4-2
configuration remote (CNR) 4-10
connect incoming call (CIC), 4-9
connector
EIA-232 D-1
connector type for DTE, 6-5
connector type option, 6-5
customer service, xi

D
C
call request using stored number (CRS), 4-11
call request with number (CRN), 4-10
Canadian emissions requirements, vii
Canadian equipment limitations vi
cancel key, on front panel, 3-5
CAPS department
how to contact, xii
carrier detect (CD) 6-13

61202011L1-1

data buffering
specifications, F-2
data format
AT commands B-5
data format for DTE interface, 6-6
data service rates
specifications, F-1
data set ready (SR)
AT commands B-7

DSU III AR User Manual

Index-1

Index

data set ready (SR) options, 6-15
data terminal ready (TR) menu, 6-14
DDS network status messages, 12-3
DDS tail circuit, E-1
diagnostic testing, 11-1
diagnostics
specifications, F-2
dial backup
configuration 8-1
dial menu, 3-2
dial options
auto answer, 8-2
phone number storage, 8-1
dial options menu, 8-1
dial selection 10-1
digital data service (DDS) 1-1, 5-6
disregard incoming call (DIC), 4-11
DSU operational status messages, 12-2
DSU/CSU status messages, 11-5
DTE and Loop test, 11-12
DTE command option 6-7
DTE connectors 2-3
DTE control leads and status messages, 12-4
DTE data connection 2-4
DTE interface 2-3
DTE interface parameters 4-1
DTE interfaces
specifications, F-1
DTE only test, 11-16
DTE options menu, 6-1
DTE rate
over 56/64 kbps loop, 6-2
DTE Rate/Mode status message, 12-4
DTE rates
specifications, F-1

F
FCC approval
specifications, F-1
FCC radio frequency interference statement, v
FCC regulations, iv
Front panel
description of, 3-5
front panel
LED descriptions, 3-6
front panel menu structure,
menu for front panel, 3-1
function keys for menu travel, 3-3

H
help desk
how to contact, xi

I
installation 2-1

L
LCD window on front panel, 3-5
LED descriptions, on front panel, 3-6
line interface
specifications, F-2
line requirements
specifications, F-2
local configuration, about, 4-1
local unit diagnostics, 11-10
loop only (RT) test, 11-14
loop rate option, 5-1

M
E
EIA local loopback, 7-3
EIA remote loopback, 7-4
EIA-232 connector D-1
EIA-232 interface 1-1
enter dial number option, 10-2
enter key, on front panel, 3-5
environmental
specifications, F-3
exiting a test, 11-3
external clock 6-9

Index-2

main menu 3-1, 3-6
manual command 4-1
manual command option, 9-1
menu travel, 3-3
modem tail circuit application, E-1

N
network
interface connection 2-4
network address 5-3
network interface parameters, 4-1
network options 5-1
for loop operation, 5-1
DSU III AR User Manual

61202011L1-1

Index

AT commands B-5
secondary channel 2-3
connection 2-4
services 2-3
secondary rate
AT commands B-8
secondary rate options, 6-16
self test option, 11-22
serial connection
of two DDS circuits, E-1
service type information iv
shift key, on front panel, 3-6
specifications, F-1
status menu, 3-2
switched 56 operation, 4-10
switched mode dialing options
specifications, F-2

network rate status message, 12-4
numeric keypad, on front panel, 3-5

O
operating modes
specifications F-1
operation 3-1

P
phone number storage
AT commands B-9
pinouts
auxiliary EIA-232 connector, A-4
primary EIA-232 connector, A-2
primary V.35 connector, A-3
telco connector, A-1
point-to-point operation 6-4
power cord 2-3
power switch 2-3
power up 2-2
primary EIA-232 2-3
primary V.35 2-3
product support, xi
product warranty, x
program number (PRN), 4-11

Q
quick key, on front panel, 3-6

R
rear panel 2-3
receiver sensitivity
specifications, F-2
redial last number option, 10-2
remote configuration
AT commands B-2, B-3
enable/disable 5-4
remote configuration, about, 4-1
remote digital loopback (RDL) option, 7-2
repair and return information, xii
request list of numbers (RLN), 4-12
RMA requests xi

technical support
how to contact, xi
telco jack 2-3
test AT commands, 11-10
test menu, 3-2
test options
configuration 7-1
test options menu, 7-1
test pattern option, 11-20
test time-out 7-1
test timeout
AT commands B-8
testing
diagnostic, troubleshooting, 11-1
timing source, 5-6
trademark information, ii
training information
how to contact, xii
transmit clock 6-8
AT command B-5
troubleshooting
test sequence for new installs or existing circuits, 11-8
troubleshooting new installs 11-6

U
S
safety instructions, vii
scrambler on/off 6-3

61202011L1-1

unit dialing options, 4-1
unit test options, 4-1
up and down arrows, on front panel, 3-5
user profiles 4-1
DSU III AR User Manual

Index-3

Index

V
V.25 bis commands 4-7
asynchronous option 4-8
bi-sync option 4-7
possible responses to, 4-9
SDLC option 4-7

Index-4

V.35 connector 2-4
VALA 4-9

W
warranty, x

DSU III AR User Manual

61202011L1-1

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