Paradyne COMSPHERE 3920PLUS Series Product manual

COMSPHERE
392XPLUS MODEMS
MODELS 3920PLUS
AND 3921PLUS
TECHNICAL REFERENCE MANUAL
Document No. 3920-A2-GH30-40

COMSPHERE
392xPLUS MODEMS
MODELS 3920PLUS
AND 3921PLUS
TECHNICAL REFERENCE MANUAL
Document No. 3920-A2-GH30-40
October 1998

COMSPHERE 392xPlus Modems
AOctober 1998 3920-A2-GH30-40
COMSPHERE
392xPlus Modems
Models 3920Plus and 3921Plus
Technical Reference Manual
3920-A2-GH30-40
5th Edition (October 1998)
Changes and enhancements to the product and to the information herein will be documented and issued as a new release or
a Firmware Update Description document to this manual.
For the Model 3920Plus standalone modems, the Universal Service Order Code (USOC) for Permissive mode is RJ11C.
The Canadian equivalent to RJ11C is CA11A. For the 3921Plus carrier-mounted modems, the USOC for Permissive mode
is RJ21X. The Canadian equivalent to RJ21X is CA21A.
For regulatory approval, refer to the product labeling or contact your local representative.
Warranty, Sales, and Service Information
Contact your local sales representative, service representative, or distributor directly for any help needed. For additional
information concerning warranty, sales, service, repair, installation, documentation, training, distributor locations, or
Paradyne worldwide office locations, use one of the following methods:
HVia the Internet: Visit the Paradyne World Wide Web site at http://www.paradyne.com
HVia Telephone: Call our automated call system to receive current information via fax or to speak with a company
representative.
— Within the U.S.A., call 1-800-870-2221
— Outside the U.S.A., call 1-727-530-2340
Trademarks
All products and services mentioned herein are the trademarks, service marks, registered trademarks or registered service
marks of their respective owners.
COPYRIGHT E1998 Paradyne Corporation. All rights reserved.
Thispublicationis protected by federalcopyright law. No part ofthis publication may becopied or distributed, transmitted,transcribed,storedin a retrieval system,
ortranslatedintoanyhumanorcomputerlanguageinanyformorbyanymeans,electronic,mechanical,magnetic,manualorotherwise,ordisclosedtothirdparties
without the express written permission of Paradyne Corporation, 8545 126th Avenue North, P.O. Box 2826, Largo, Florida 33779-2826.
ParadyneCorporationmakesnorepresentationorwarrantieswithrespecttothecontentshereofandspecificallydisclaimsanyimpliedwarrantiesofmerchantability
orfitness for a particular purpose. Further,ParadyneCorporationreservestherighttorevisethispublicationand to make changes from time to time in the contents
hereof without obligation of Paradyne Corporation to notify any person of such revision or changes.
Printed on recycled paper

Safety Instructions
B3920-A2-GH30-40 October 1998
Important Safety Instructions
1. Read and follow all warning notices and instructions marked on the product or included in the
manual.
2. Some models are provided with a three-wire grounding type plug –a plug which has a
grounding pin. This is a safety feature. Equipment grounding is vital to ensure safe operation.
Do not defeat the purpose of the grounding type plug by modifying the plug or using an
adapter.
Prior to installation, use an outlet tester or a voltmeter to check the ac receptacle for the
presence of earth ground. If the receptacle is not properly grounded, the installation must not
continue until a qualified electrician has corrected the problem.
If a three-wire grounding type power source is not available, consult a qualified electrician to
determine another method of grounding the equipment.
3. Slots and openings in the cabinet are provided for ventilation. To ensure reliable operation of
the product and to protect it from overheating, these slots and openings must not be blocked
or covered.
4. Do not allow anything to rest on the power cord and do not locate the product where persons
will walk on the power cord.
5. Do not attempt to service this product yourself, as opening or removing covers may expose
you to dangerous high voltage points or other risks. Refer all servicing to qualified service
personnel.
6. General purpose cables are provided with this product. Special cables, which may be required
by the regulatory inspection authority for the installation site, are the responsibility of the
customer.
7. When installed in the final configuration, the product must comply with the applicable Safety
Standards and regulatory requirements of the country in which it is installed. If necessary,
consult with the appropriate regulatory agencies and inspection authorities to ensure
compliance.
8. A rare phenomenon can create a voltage potential between the earth grounds of two or more
buildings. If products installed in separate buildings are interconnected, the voltage potential
may cause a hazardous condition. Consult a qualified electrical consultant to determine
whether or not this phenomenon exists and, if necessary, implement corrective action prior to
interconnecting the products.
9. In addition, if the equipment is to be used with telecommunications circuits, take the
following precautions:
–Never install telephone wiring during a lightning storm.
–Never install telephone jacks in wet locations unless the jack is specifically designed for
wet locations.
–Never touch uninsulated telephone wires or terminals unless the telephone line has been
disconnected at the network interface.
–Use caution when installing or modifying telephone lines.
–Avoid using a telephone (other than a cordless type) during an electrical storm.
There may be a remote risk of electric shock from lightning.
–Do not use the telephone to report a gas leak in the vicinity of the leak.

COMSPHERE 392xPlus Modems
COctober 1998 3920-A2-GH30-40
Notices
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 COMMUNICATIONS. 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.
THE AUTHORITY TO OPERATE THIS EQUIPMENT IS CONDITIONED BY THE REQUIREMENTS THAT NO
MODIFICATIONSWILL BE MADETOTHE EQUIPMENT UNLESS THE CHANGES OR MODIFICATIONS ARE EXPRESSLY
APPROVED BY PARADYNE.
WARNING
WARNING
TO USERS OF DIGITAL APPARATUS IN CANADA:
THIS CLASS [A] DIGITAL APPARATUS MEETS ALL REQUIREMENTS OF THE CANADIAN INTERFACE-CAUSING
EQUIPMENT REGULATIONS.
CET APPAREIL NUMERIQUE DE LA CLASSE [A] RESPECTE TOUTES LES EXIGENCES DU REGLEMENT SUR LE
MATERIEL BROUILLEUR DU CANADA.

i3920-A2-GH30-40 October 1998
Table of Contents
Preface
Objectives and Reader Assumptions vii. . . . . . . . . . . . . . . . . . . . . . . . .
How to Use This Manual vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Related Documents viii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Introduction
Overview 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMSPHERE 392xPlus Models 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Operational Modes 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Modem Features 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Singleport Modem Features 1-7. . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Multiport Modem Features 1-7. . . . . . . . . . . . . . . . . . . . . . . .
Applications 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Government Requirements and Equipment Return 1-10. . . . . . . . . . . . . .
Technical Specifications 1-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Modem Installation
Overview 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Modem Package 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model 3920Plus Modem Installation 2-3. . . . . . . . . . . . . . . . . . . . . . . . .
Connecting Cables to the Model 3920Plus Modem 2-3. . . . . . . . . . . . .
Removing and Replacing the Model 3920Plus Modem 2-8. . . . . . . . . .
Model 3921Plus Modem Installation 2-8. . . . . . . . . . . . . . . . . . . . . . . . .
Removing the Model 3921Plus Modem 2-13. . . . . . . . . . . . . . . . . . . . . .
392xPlus Modem Power-Up 2-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting Factory Configuration Options 2-13. . . . . . . . . . . . . . . . . . . . .
3. DCP Operation
Overview 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Control Panels 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Indicators 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Control Panel Operation 3-6. . . . . . . . . . . . . . . . . . . . . . . . .
Menu Structure 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMSPHERE 392xPlus Modems
ii October 1998 3920-A2-GH30-40
4. Status Branch
Status Branch 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5. Configure Branch
Overview 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configure Branch 5-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Tables 5-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multiport Mode 5-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Singleport Mode 5-35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6. Poll List Branch
Poll List Branch 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7. Control Branch
Control Branch 7-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8. Test Branch
Test Branch 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9. Sub-Network Health and Status Branch
Sub-Network Health and Status Branch 9-1. . . . . . . . . . . . . . . . . . . . . .
10. Call Setup Branch
Call Setup Branch 10-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11. Talk/Data Branch
Talk/Data Branch 11-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12. Dial Access Security
Overview 12-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Security Branch 12-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Security Configuration Options 12-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Security Password Entry Techniques 12-16. . . . . . . . . . . . . . . . . . . . . . . . .
Database Table Examples 12-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13. Remote Branch
Remote Branch 13-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents
iii3920-A2-GH30-40 October 1998
14. AT Command Set and S-Registers
Overview 14-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Command and Data Modes 14-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Command Guidelines 14-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AT Command List 14-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S-Register List 14-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendices
A. Menu Tree A-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B. Troubleshooting B-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C. Pin Assignments C-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D. ITU-T V.25bis Dialing Commands and Responses D-1. . . . . . . . . .
E. ASCII Character Table E-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
F. Default Configuration Options F-1. . . . . . . . . . . . . . . . . . . . . . . . .
G. Sample Configurations G-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H. Synchronous Data Compression H-1. . . . . . . . . . . . . . . . . . . . . . . .
I. Equipment List I-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glossary
Index

COMSPHERE 392xPlus Modems
iv October 1998 3920-A2-GH30-40
List of Figures
Figure Page
1-1 3920-A2 Standalone Modem 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-2 3920-A1 Standalone Singleport and Multiport Modems 1-3. . . . . . . . . . . . . . . . . . . . . .
1-3 Model 3921Plus Singleport Modem 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-4 Model 3921Plus Multiport Modem 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1 Model 3920Plus Singleport (3920-A2-xxx) Back Panel and Power Supply 2-4. . . . . . .
2-2 Model 3920Plus Multiport Back Panel and Power Supply 2-5. . . . . . . . . . . . . . . . . . . .
2-3 Model 3921Plus Back Connector Plates 2-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-4 Installing the Model 3921Plus Modem 2-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-5 Circuit Pack Lock 2-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1 Model 3920Plus DCP 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-2 Optional SDCP and Model 3921Plus Faceplates 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . .
3-3 392xPlus LCD and Keypad 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-1 DCP Configuration Process 5-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-1 Local Analog Loopback 8-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-2 Remote Digital Loopback 8-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-3 Local Digital Loopback 8-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-4 Pattern Test and Local Analog Loopback Test 8-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-5 Pattern Test and Digital Loopback Test 8-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-6 End-to-End Pattern Test 8-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10-1 Dial Backup 10-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C-1 VF Pin Orientation C-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C-2 Wiring Diagram —“Y”Cable for External Telephone C-4. . . . . . . . . . . . . . . . . . . . . . .
C-3 Wiring Diagram —8-Position to 6-Position Crossover Cable C-5. . . . . . . . . . . . . . . . .
C-4 Wiring Diagram —25-Pin Crossover Cable C-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-1 Sample Configuration —Point-to-Point G-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-2 Sample Configuration —Extended Point-to-Point G-4. . . . . . . . . . . . . . . . . . . . . . . . . .
G-3 Sample Configuration —Extended Multipoint G-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-4 Sample Configuration —Point-to-Point with Automatic Dial Backup G-8. . . . . . . . . .
G-5 Sample Configuration —Point-to-Point with Network Management G-10. . . . . . . . . . .
G-6 Sample Configuration —Carrier with Network Management G-12. . . . . . . . . . . . . . . . .
G-7 Sample Configuration —Extended Diagnostics G-14. . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-8 Sample Configuration —Digital Bridge G-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-9 Sample Configuration —Point-to-Point MSD G-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-10 Sample Configuration —Multipoint MSD G-20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H-1 Sample DTE Exchange of Data via Synchronous Protocol and SDC H-1. . . . . . . . . . . .
H-2 Synchronous Data Compression H-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H-3 Synchronous Data Format H-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H-4 Clocks at the DTE–DCE Interface H-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents
v3920-A2-GH30-40 October 1998
List of Tables
Table Page
1-1 392xPlus Operational Modes 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-2 Technical Specifications for 392xPlus Modems 1-13. . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1 392xPlus DCP LEDs 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-2 SDCP LEDs 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-3 Top-Level Menu Status 3-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-4 Common Operational Messages 3-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-5 Dial Access Security Messages 3-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-1 Health and Status Messages 4-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-2 SDC Performance Measurements 4-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-3 Backup Status Screens 4-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-1 DTE Interface Configuration Options —Multiport Mode 5-10. . . . . . . . . . . . . . . . . . . .
5-2 Line Dialer Configuration Options —Multiport Mode 5-19. . . . . . . . . . . . . . . . . . . . . .
5-3 Dial Line Configuration Options —Multiport Mode 5-22. . . . . . . . . . . . . . . . . . . . . . . .
5-4 Leased Line Configuration Options —Multiport Mode 5-25. . . . . . . . . . . . . . . . . . . . . .
5-5 Test Configuration Options —Multiport Mode 5-30. . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-6 Miscellaneous Configuration Options —Multiport Mode 5-31. . . . . . . . . . . . . . . . . . . .
5-7 DTE Interface Configuration Options —Singleport Mode 5-37. . . . . . . . . . . . . . . . . . .
5-8 DTE Dialer Configuration Options —Singleport Mode 5-45. . . . . . . . . . . . . . . . . . . . . .
5-9 Line Dialer Configuration Options —Singleport Mode 5-49. . . . . . . . . . . . . . . . . . . . . .
5-10 Dial Line Configuration Options —Singleport Mode 5-53. . . . . . . . . . . . . . . . . . . . . . .
5-11 Leased Line Configuration Options —Singleport Mode 5-57. . . . . . . . . . . . . . . . . . . . .
5-12 V.42/MNP/Buffer Configuration Options —Singleport Mode 5-64. . . . . . . . . . . . . . . . .
5-13 Test Configuration Options —Singleport Mode 5-71. . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-14 Miscellaneous Configuration Options —Singleport Mode 5-73. . . . . . . . . . . . . . . . . . .
7-1 Valid Ranges for VF Thresholds 7-20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10-1 Valid Dial Command Modifiers 10-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12-1 Edit Password Table Group Options 12-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12-2 Set Answer Security Group Options 12-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12-3 Set Originate Security Group Options 12-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12-4 Security Configuration Options 12-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12-5 Security Database Table Using VF-Side Passwords 12-18. . . . . . . . . . . . . . . . . . . . . . . . .
12-6 Security Database Table Using DTE-Side Passwords 12-18. . . . . . . . . . . . . . . . . . . . . . . .
12-7 Security Database Table Using Both VF-Side and DTE-Side Passwords 12-19. . . . . . . . .
14-1 Result Codes 14-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14-2 392xPlus AT Commands 14-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14-3 392xPlus S-Registers 14-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMSPHERE 392xPlus Modems
vi October 1998 3920-A2-GH30-40
Table Page
B-1 Modem Health B-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-2 Leased-Line Operation B-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-3 Dial Backup Operation B-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-4 Modem —DTE Connection B-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-5 Modem —VF Connection B-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-6 Online Operation B-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-7 Misc Operation B-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B-8 Mux Operation B-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C-1 EIA-232-D Pin Assignments C-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C-2 VF Connector Pin Assignments C-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D-1 V.25bis Commands D-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D-2 V.25bis Response Messages D-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
E-1 ASCII Characters E-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
F-1 Factory Default Configuration Options F-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H-1 SDC Negotiation Configuration Scenarios H-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii3920-A2-GH30-40 October 1998
Preface
Objectives and Reader Assumptions
This manual describes how to install and operate the COMSPHERE Model 3920Plus standalone
and Model 3921Plus carrier-mounted modems. Users of this manual must have a basic
understanding of modems and their operation.
How to Use This Manual
Chapter 1 provides technical specifications, information about the four 392xPlus models, the
modem features, and the government requirements for using these modems.
Chapter 2 provides instructions for installing the 392xPlus modems.
Chapter 3 provides the information required to operate the Model 3920Plus using the diagnostic
control panel and the Model 3921Plus using the COMSPHERE 3000 Series Carrier’s shared
diagnostic control panel (SDCP).
Chapter 4 provides information about the Status branch of the DCP menu.
Chapter 5 provides the information required to set configuration options in the 392xPlus modems
using the modem’s diagnostic control panel.
Chapter 6 provides information about the Poll List branch of the DCP menu.
Chapter 7 provides information about the Control branch of the DCP menu.
Chapter 8 provides information about the Test branch of the DCP menu.
Chapter 9 provides information about the Sub-Network Health and Status branch of the DCP
menu.
Chapter 10 provides information about the Call Setup branch of the DCP menu.
Chapter 11 provides information about the Talk/Data branch of the DCP menu.
Chapter 12 provides instructions for using the Dial Access Security feature.
Chapter 13 provides information about the Remote branch of the DCP menu.
Chapter 14 provides instructions for using AT commands and S-Registers.
Appendix A provides a menu tree for the 392xPlus modems.
Appendix B provides instructions for performing diagnostic tests when data communication
problems occur.

COMSPHERE 392xPlus Modems
viii October 1998 3920-A2-GH30-40
Appendix C provides EIA-232-D and VF TELCO pin assignments.
Appendix D provides V.25bis dialing information.
Appendix E provides an ASCII translation chart.
Appendix F provides a list of all default configuration options available for the factory preset
configurations.
Appendix G provides diagrams of sample configurations for the 392xPlus modems.
Appendix H provides Synchronous Data Compression information.
Appendix I provides an equipment list for the 392xPlus modems.
The Glossary provides a description of terms used throughout this manual.
Related Documents
3000-A2-GA31 COMSPHERE 3000 Series Carrier, Installation Manual
3610-A2-GZ45 3600 Hubbing Device, Feature Number 3600-F3-300, Installation
Instructions
3920-A2-GK40 COMSPHERE 3900 Series Modems, Model 3921Plus, Ferrite Choke,
Installation Instructions
3920-A2-GK41 COMSPHERE 392xPlus Modems, Models 3920Plus and 3921Plus,
Installation Instructions
3920-A2-GK47 COMSPHERE 392xPlus Modems, Model Number 3920-A2-411,
Installation Instructions
Contact your sales or service representative to order additional product documentation.
Paradyne documents are also available on the World Wide Web at:
http://www.paradyne.com
Select Service & Support Technical Manuals

1-13920-A2-GH30-40 October 1998
Introduction
Overview 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMSPHERE 392xPlus Models 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model 3920Plus Standalone Singleport Modems 1-2. . . . . . . . . . . . . . . . . . .
Model 3920Plus Standalone Multiport Modem 1-3. . . . . . . . . . . . . . . . . . . .
Model 3921Plus Singleport Carrier-Mounted Modem 1-4. . . . . . . . . . . . . . .
Model 3921Plus Multiport Carrier-Mounted Modem 1-5. . . . . . . . . . . . . . . .
392xPlus Operational Modes 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Modem Features 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Singleport Modem Features 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
392xPlus Multiport Modem Features 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Applications 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multipoint 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dual-Leased Backup 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MSD 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Bridge 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V.34 Modulation 1-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multiport Backup 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Synchronous Data Compression 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Government Requirements and Equipment Return 1-10. . . . . . . . . . . . . . . . . . . .
United States 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Canada 1-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Specifications 1-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview
The COMSPHERE 392xPlus modems are full-feature, high-speed leased modems, providing
reliable asynchronous and synchronous operation over leased- or dial-line networks with data rates
as high as 33,600 bps.
Through downloading capability, any 392xPlus modem is upgradable to the latest firmware,
requiring no new hardware investment or on-site personnel, with little or no downtime (refer to
Chapter 3, DCP Operation,for more information regarding downloading options). The 392xPlus
modems support a wide range of modulation schemes and offer control using either AT commands,
the diagnostic control panel (DCP), or the optional COMSPHERE 6700 and 6800 Series Network
Management Systems (NMS). The NMS performs extensive monitoring, testing, reporting, and
restoral functions to assist in managing your network.
The 392xPlus modems are compatible with a number of dialing methods and protocols, such as
asynchronous AT commands, ITU-T V.25bis dialing, and the DCP. The DCP allows you to use the
392xPlus modem in a variety of applications and environments while also providing control over
modem configuration, dialing, and diagnostics. The 392xPlus modems come with preset factory
configurations that are the most often used modem settings.
1

COMSPHERE 392xPlus Modems
1-2 October 1998 3920-A2-GH30-40
COMSPHERE 392xPlus Models
The COMSPHERE 392xPlus modem is available in the following models:
•Model 3920Plus standalone singleport modem (model no. 3920-A1-xxx and 3920-A2-xxx).
•Model 3920Plus standalone multiport modem (model no. 3920-A1-40x).
•Model 3921Plus carrier-mounted singleport modem (model no. 3921-B1-01x).
•Model 3921Plus carrier-mounted multiport modem (model no. 3921-B1-00x).
A reference to 392xPlus modems refers to all 3920Plus and 3921Plus models.
Model 3920Plus Standalone Singleport Modems
The Model 3920Plus singleport (Figures 1-1 and 1-2) is a standalone modem capable of either
4-wire/2-wire leased-line or dial operation. This modem is controlled using either AT commands
or the DCP. The DCP consists of a liquid crystal display (LCD), three function keys, four
directional keys, and a row of 13 LED status indicators. For a better understanding of DCP
operation, refer to Chapter 3, DCP Operation.
DIAGNOSTIC
CONTROL
PANEL
LCD AND
KEYPAD
STATUS
INDICATORS
POWER
SUPPLY
97-14678-02
POWER
ON/OFF
LEASED
DIAL
DTE 1
NMS
POWER IN
Figure 1-1. 3920-A2 Standalone Modem

Chapter Title
1-33920-A2-GH30-40 October 1998
Model 3920Plus Standalone Multiport Modem
The Model 3920Plus multiport is a standalone modem (Figure 1-2), with an integral time division
multiplexer (TDM) and a modem sharing device (MSD) as standard equipment. The TDM
provides time division multiplexing of up to four independent ports over point-to-point lines using
the V.34 family or V.32 family modulation. The MSD allows multiple physical ports on a tributary
modem to share a single communication channel using the V.34 family, V.32 family, or TMp
modulation. The TDM/MSD multiplexer (commonly referred to as “mux”) can be enabled or
disabled to allow a greater degree of application flexibility.
The 3920Plus multiport modem also operates over a 4-wire/2-wire leased or dial network and is
controlled using the same DCP employed on the Model 3920Plus singleport standalone modem.
DIAGNOSTIC
CONTROL
PANEL
LCD AND
KEYPAD
STATUS
INDICATORS
SPEAKER POWER
SUPPLY
POWER
CORD
496-14684-01
LEASED
Model 3920Plus Singleport and
Multiport Housing
Singleport Modem
Back Panel Multiport Modem
Back Panel
POWER
ON/OFF
DIAL DTE 1NMS
POWER IN
DTE 2
DTE 3
DTE 4
POWER
ON/OFF
LEASED
DIALDTE 1
NMS
POWER IN
Figure 1-2. 3920-A1 Standalone Singleport and Multiport Modems

COMSPHERE 392xPlus Modems
1-4 October 1998 3920-A2-GH30-40
Model 3921Plus Singleport Carrier-Mounted Modem
The Model 3921Plus singleport is a carrier-mounted modem (Figure 1-3) capable of either
4-wire/2-wire leased-line or dial operation. The modem installs into a COMSPHERE 3000 Series
Carrier, occupying a single slot. The modem’s faceplate has sixteen (16) LED status indicators for
displaying modem activity and an audio speaker jack for the carrier’s optional speaker.
The modem’s back panel has two edge card connectors that mount into a connector plate. This
connector plate has two DB-25-S connectors, one providing an EIA-232-D DTE interface and one
for future functionality.
FACEPLATE
496-14178a-04
EIA232/V.24
EDGE CARD
CONNECTOR
FUTURE
USE
BACK
CONNECTOR
PLATE
V.35
(3600/3500)
RS366A/V.25
(3800)
EIA232/V.24
TXD
RXD
RTS
CTS
DSR
DTR
LSD
103
104
105
106
107
108
109
Pwr
Alrm
Test
Dial
RI
Busy
Serv
SQ
Status
Front Panel
3921Plus
142
125
Spkr
EIA232/V.24
CONNECTOR
FUTURE
USE
GROUNDING
TAB
Figure 1-3. Model 3921Plus Singleport Modem

Introduction
1-53920-A2-GH30-40 October 1998
Model 3921Plus Multiport Carrier-Mounted Modem
The Model 3921Plus multiport is a carrier-mounted modem (Figure 1-4) equipped with an integral
time division multiplexer (TDM) with a modem sharing device (MSD). The modem installs into
the COMSPHERE 3000 Series Carrier, occupying two slots. The modem’s faceplate covers two
slots in the carrier. It has twenty (20) LED status indicators for displaying modem activity and an
audio speaker jack for the carrier’s optional speaker.
The modem’s back panel has four edge card connectors that mount into two connector plates. Each
connector plate has two DB-25-S connectors providing four EIA-232-DTE interfaces.
Both the singleport and multiport Model 3921Plus modems derive ac power from the
COMSPHERE 3000 Series Carrier’s backplane, which is a common bus to all devices installed in
the carrier. The user interface to any Model 3921Plus modem is through the shared diagnostic
control panel (SDCP), an optional feature which operates in a manner similar to the DCP on the
Model 3920Plus modems.For a better understanding of DCP operation, refer to Chapter 3,
DCP Operation.
49614423a-03
FACEPLATE
EDGE CARD
CONNECTORS
PORT
3
PORT
4
PORT
1
PORT
2
3921Plus
TXD
RXD
RTS
CTS
DSR
DTR
LSD
Pwr
Alrm
Test
Dial
RI
Busy
Serv
SQ
Status
Front Panel
Spkr
142
125
103
104
105
106
107
108
109
13
24
Port
BACK
CONNECTOR
PLATES
DTE B DTE A DTE B DTE A
Figure 1-4. Model 3921Plus Multiport Modem

COMSPHERE 392xPlus Modems
1-6 October 1998 3920-A2-GH30-40
392xPlus Operational Modes
The 392xPlus operational modes determine how your modem performs in various applications.
These operational modes are determined by your modem model and the selected configuration
options.
There are two operational modes:
•Singleport. Operates on both the singleport and multiport modem models. The Singleport
mode only supports one port (DTE 1). Singleport mode is the only operational mode for the
singleport modem models. For the multiport modem models, Singleport mode is in effect
when the MUX Mode configuration option is set to Disable.
•Multiport. Operates only on the multiport modem models. Multiport mode is in effect when
the MUX Mode configuration option is set to TDM/MSD or DTE_Bridge. It supports from
one to four ports (DTE 1–4), depending on how the modem is configured.
Using Table 1-1, identify your modem’s operational mode based on the 392xPlus modem model
and its selected MUX mode configuration option.
Table 1-1
392xPlus Operational Modes
392xPlus Modem MUX Mode Configuration Option Operational Mode
Singleport n/a Singleport
Multiport MUX Mode: Disabled
MUX Mode set to:TDM/MSD, DTE_Bridge Singleport Multiport
Use the identified operational mode (Singleport or Multiport) to choose the configuration options
that are appropriate for your modem’s application. Refer to Chapter 5, Configure Branch, for
information on configuration options.

Introduction
1-73920-A2-GH30-40 October 1998
392xPlus Modem Features
The 392xPlus modems share a wide variety of features.
•Asynchronous DTE rates of 115.2 kbps and 76.8 kbps.
•Asynchronous data compression and error correction.
•Synchronous data compression.
•Additional VF parameters under the V.32 and V.34 family modulations in 4-wire mode.
•International Support to correctly detect the call progress signals (dial tone, busy, fast busy,
ringback) for a variety of countries.
•Channel adaptive Trellis-Coded Modulation –Paradyne’s advanced Trellis-Coded
transparent forward error correction for Trellis multipoint and high-speed point-to-point
applications.
•Convenient migration to new or optional features through software downloading.
•Extended data circuits with diagnostic capabilities.
•Network management system (NMS) support through the COMSPHERE 6800 or
6700 Series NMS using Advanced Diagnostic protocol (ADp).
•Automatic and manual backup with standby capabilities for 4-wire/2-wire leased-line
applications. (The backup facility may be either a 2-wire dial line or a 2-wire leased line.)
392xPlus Singleport Modem Features
Features specific to 392xPlus singleport modems are:
•Four-wire/two-wire leased-line modulations.
•Dial-line modulations.
Refer to Table 1-2 in the Technical Specifications section of this chapter for leased- and dial-line
modulations information.
392xPlus Multiport Modem Features
Features specific to 392xPlus multiport modems are:
•Four-port time division multiplexer (TDM) operation.
•Modem Sharing Device (MSD).
•Digital Bridging.
•Mux enabled, four-wire/two-wire leased-line modulations: V.34 (33,600, 28,800, 24,000,
19,200, 16,800, 14,400, 12,000, 9600, 7200, 4800, and 2400 bps), V.32terbo (19,200 and
16,800 bps), V.32bis (14,400, 12,000, 9600, 7200, and 4800 bps), V.32 (9600 and 4800 bps),
and Trellis Multipoint (TMp) (19,200, 14,400, 9600, 7200, 4800, and
2400 bps).
•Mux enabled, dial-line modulations: V.34 (33,600, 28,800, 24,000, 19,200, 16,800, 14,400,
12,000, 9600, 7200, 4800, and 2400 bps), V.32terbo (19,200 and 16,800 bps), V.32bis
(14,400, 12,000, 9600, 7200, and 4800 bps), V.32 (9600 and 4800 bps).