Multi-Tech Systems BL User Manual
BL-Series
Intelligent Data/Fax Modem
User Guide
User Guide
88312100 Revision A
MultiModem
MT2834BL/MT2834BLI/MT2834BLK
MT1932BL/MT1932BLI/MT1932BL-Mac
MT1432BL/MT1432BLI/MT1432BLK
This publication may not be reproduced, in whole or in part, without prior expressed written
permission from Multi-Tech Systems, Inc.
All rights reserved.
Copyright 1999 ©, by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representations or warranties with respect to the contents hereof
and specifically disclaims any implied warranties of merchantability or fitness for any particular
purpose. Furthermore, Multi-Tech Systems, Inc. reserves the right to revise this publication and to
make changes from time to time in the content hereof without obligation of Multi-Tech Systems, Inc.
to notify any person or organization of such revisions or changes.
Record of Revisions
A (6/1/99) Manual formatted for electronic distribution. All pages at Revision A.
Trademarks of Multi-Tech Systems, Inc. are as follows:
II
Models:
MultiModemII, Multi-Tech and the Multi-Tech logo.
MNP, Microcom Network Protocol is a trademark of Microcom Inc.
AS/400 and System3x is a trademark of IBM.
Macintosh is a trademark of Apple Computer Inc.
Unix is a trademark of X/Open Co. Ltd.
Windows® and Windows® 95 are registered trademarks of Microsoft
All other brands and product names mentioned in this publication are trademarks or registered
trademarks of their respective companies.
Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112 U.S.A.
(612) 785-3500 or (800) 328-9717
U. S. FAX 612-785-9874
Fax-Back Service 612-717-5888
Technical Support (800) 972-2439
BBS (612) 785-3702 or (800) 392-2432
Internet Address: http://www.multitech.com
Technical Writer: brian@multitech.com
Contents
Chapter 1 - Introduction and Description
1.1 Introduction...................................................................................................................................... 8
1.2 How To Use This Manual................................................................................................................. 8
1.3 Modem Features ............................................................................................................................. 10
1.3.1 2834 Series Features................................................................................................................ 10
1.3.2 1932 Series Features................................................................................................................ 10
1.3.3 1432 Series Features................................................................................................................ 11
1.4 Fax Features ................................................................................................................................... 11
1.5 T echnical Specifications .................................................................................................................. 12
1.6 Power .............................................................................................................................................. 16
1.7 Modem LED Indicators.................................................................................................................... 16
1.8 Controls on PC Board ..................................................................................................................... 17
Chapter 2 - Installation and Connection
2.1 What is in Your Modem Package? .................................................................................................. 20
2.2 Installation ....................................................................................................................................... 21
2.2.1 Safety Warnings........................................................................................................................ 21
2.2.2 Installation Procedure ............................................................................................................... 21
2.2.3 Cabling Procedure (MT1432BL/BLI, MT1932BL/BLI, and MT2834BL/BLI) .............................. 21
2.2.4 Cabling Procedure (MT1432BLK and MT2834BLK) ................................................................. 23
2.3 Loading Trio DataFAX Software ...................................................................................................... 24
2.4 Is Your Modem Ready for Use? ...................................................................................................... 26
Chapter 3 - Software Configuration and Modem Basics
3.1 Introduction...................................................................................................................................... 28
3.2 Serial Port Limitations ..................................................................................................................... 28
3.2.1 How Can Y ou Identify Your UART T ype?.................................................................................. 28
3.2.2 The 16550 UART and Windows 3.1.......................................................................................... 29
3.3 Configuring Y our Software............................................................................................................... 29
3.3.1 ConfiguringSoftware for Your Modem ....................................................................................... 29
3.4 PC Initialization Strings ................................................................................................................... 30
3.4.1 Changing Default Parameters................................................................................................... 30
3.4.2 Other Parameters ..................................................................................................................... 30
3.5 Macintosh Initialization .................................................................................................................... 31
3.6 Configuring Software for Your Computer......................................................................................... 31
3.6.1 Configuring Software for the Remote System........................................................................... 31
3.6.2 T erminal Emulation ................................................................................................................... 31
3.6.3 File Transfer Protocols .............................................................................................................. 32
3.7 When to Disable Data Compression ............................................................................................... 32
3.7.1 Disabling Error Correction......................................................................................................... 32
3.8 Modem Basics................................................................................................................................. 33
3.8.1 Simple Operations .................................................................................................................... 33
3.9 The Answer/Originate - Voice/Data Toggle Switch .......................................................................... 33
iii
Chapter 4 - Manual Dial and Automatic Answer
4.1 Introduction...................................................................................................................................... 36
4.2 Dialing/On-Line/Answering .............................................................................................................. 36
4.3 Automatic Leased Line Restoral Operation.....................................................................................37
4.4 Manual Dial Backup Call Termination.............................................................................................. 37
4.5 Dial Backup and Leased Line Restoral ........................................................................................... 37
4.6 Dial-Up Operation............................................................................................................................ 38
4.7 Manual Call Origination ................................................................................................................... 38
4.8 Automatic Answering....................................................................................................................... 39
4.9 Manual Answering ........................................................................................................................... 39
4.10 Handshaking Details ....................................................................................................................... 40
4.1 1 Call T ermination............................................................................................................................... 40
Chapter 5 - Command Mode
5.1 Introduction...................................................................................................................................... 42
5.1.1 A T Command Editing ................................................................................................................ 42
5.1.2 Functional Modes...................................................................................................................... 43
5.2 Summary of AT Commands............................................................................................................. 44
5.3 Result Codes................................................................................................................................... 47
5.4 Dialing Commands .......................................................................................................................... 49
5.4.1 Dialing Action Commands ......................................................................................................... 49
5.4.2 Dial Modifier Commands........................................................................................................... 50
5.4.3 Phone Number Memory Commands......................................................................................... 53
5.4.4 Configuration and Default Storage Commands ........................................................................ 54
5.4.5 Command Response (Result Code) Commands...................................................................... 56
5.4.6 Phone Line Conditioning Commands........................................................................................ 58
5.4.7 RS-232C Interface Control Commands .................................................................................... 61
5.4.8 Error Correction Commands ..................................................................................................... 63
5.4.9 Flow Control Commands .......................................................................................................... 66
5.4.10 Compression, Error Correction, Flow Control, Pass-Through and Pacing Commands ............ 69
5.4.1 1 Speed Conversion Commands .................................................................................................70
5.4.12 Immediate Action Commands ................................................................................................... 73
5.4.13 Line Probe Commands (2834 Series only) ............................................................................... 75
Chapter 6 - S-Registers
6.1 Introduction...................................................................................................................................... 78
6.2 Reading and Assigning S-Register Values ......................................................................................85
6.2.1 Examples of Assigning Values .................................................................................................. 85
6.2.2 Examples of Reading V alues .................................................................................................... 85
6.3 A T Command and S-Register Summary ......................................................................................... 86
Chapter 7 - Callback Security and Remote Configuration
7.1 Introduction...................................................................................................................................... 88
7.2 Callback Feature Description .......................................................................................................... 88
7.3 Remote Configuration Description................................................................................................... 89
7.3.1 Initial Setup Procedures for Callback and Remote Configuration. ............................................ 89
7.3.2 Remote Configuration Procedures............................................................................................92
7.4 Remote Configuration and Callback Security AT Commands ......................................................... 93
7.5 Remote Configuration/Callback Security S-Registers ..................................................................... 95
iv
Chapter 8 - Modem Testing
8.1 Introduction...................................................................................................................................... 98
8.2 Local Analog Loopback Test/V.54 Loop 3........................................................................................ 99
8.3 Digital Loopback Test/V.54 Loop 2 (Local/Manual).......................................................................... 100
8.4 Digital Loopback Test/V.54 Loop 2 (Remote/Automatic) ................................................................. 101
8.5 Back-to-Back Test ........................................................................................................................... 102
8.6 Synchronous Mode Testing ............................................................................................................. 103
8.7 Local Analog Loopback T est (Synchronous Mode) ......................................................................... 103
8.8 Digital Loopback Test (Local/Manual) (Synchronous Mode) ........................................................... 104
8.9 Digital Loopback Test (Remote/Automatic) (Synchronous Mode) ................................................... 105
Chapter 9 - DIP-Switch Settings
9.1 Introduction...................................................................................................................................... 108
9.2 DIP-Switch Option Settings ............................................................................................................. 109
9.3 Speaker Volume Control ................................................................................................................. 114
9.4 Recording Option Configurations .................................................................................................... 115
Chapter 10 - Warranty, Service and Tech Support
10.1 Introduction...................................................................................................................................... 118
10.2 Limited Warranty ............................................................................................................................. 118
10.2.1 On-line Warranty Registration................................................................................................... 118
10.3 Tech Support ................................................................................................................................... 119
10.3.1 Recording Modem Information.................................................................................................. 119
10.4 Service ............................................................................................................................................ 119
10.5 The Multi-Tech BBS......................................................................................................................... 120
10.5.2 Upgrading the MultiModem ...................................................................................................... 121
10.5.3 Using FlashPro to Upgrade Modem Firmware.......................................................................... 121
10.6 About Multi-Tech’s Internet Presence.............................................................................................. 121
10.7 About the Multi-Tech Fax-Back Service .......................................................................................... 121
10.8 About Ordering Accessories............................................................................................................ 122
Appendixes
Appendix A - Troubleshooting....................................................................................................................... 124
Appendix B - ASCII Character Code/Hex/Decimal Conversion Chart.......................................................... 129
Appendix C - Dial Pulse and Tone-Dial Frequencies.................................................................................... 130
Appendix D - Command Summary............................................................................................................... 131
Appendix E - DIP-Switch Summary ............................................................................................................. 140
Appendix F - S-Register Summary .............................................................................................................. 143
Appendix G - Result Code Summary ........................................................................................................... 145
Appendix H - V.25bis Operation ................................................................................................................... 147
Appendix I - MultiModemBL Cables ............................................................................................................. 154
Appendix J - RS-232C Interface Specifications ........................................................................................... 156
Appendix K - Regulatory Information ........................................................................................................... 160
Index
v
vi
Chapter 1 - Introduction and Description
MultiModemBL User Guide
1.1 Introduction
Welcome to the world of data communications. You have acquired one of the finest intelligent
desktop data/fax modems available today, the MultiModemII BL series modem, from Multi-Tech
Systems. This User Guide covers various models within the BL series, and unless otherwise noted,
all content should be considered relevant to all models.
Your MultiModem provides data communication at the following rates:
Model
MT2834BL Series
MT1932BL Series
MT1432BL Series
*Note enhancements on V.34 code (33.6K/31.2K) is awaiting formal ITU approval; the ITU study group 14 has agreed on
the technical side of the proposal, with formal approval expected at the next ITU meeting in Geneva.
33,600 - 14,400 bps (*Enhanced V.34/V.32bis)
19,200 - 14,400 bps (V.32terbo/V.32bis)
14,400 - 300 bps (V.32bis)
Baud Rate
The MultiModem also provides other prevalent data communications standards and includes dial
backup with automatic lease line restoration, adaptive protocol enhancing used in typical Unix® batch
file transfers and support for IBM's AS/400TM and WindowsTM environments.
1.2 How To Use This Manual
This manual is divided into ten chapters. While viewing in Acrobat ReaderTM you can click on blue
text to jump to the section of the manual it references. Red, bold text indicates a hyperlink to the
Internet. If you have a Web browser active on your system, click on these text links to open the
browser and go to the referenced site. The information contained in each chapter and appendix is as
follows:
Chapter 1 - Introduction and Description
This chapter begins with a short introduction, followed by a guide (which you are now reading) to the
use of this manual. There is a discussion about what components you can expect in your modem
package. We then provide a more detailed description of the modem, including the modem’s
technical specifications. Chapter 1 includes sections covering power, LED indicators and a brief
summary of PC board controls. (Chapter 9 covers switch settings more thoroughly.)
Chapter 2 - Installation and Connection
Chapter 2 covers the procedure for connecting the modem to your computer and to the phone line.
Details are given, supported by illustrations on the modem's back panel connections as a guide to
install your modem to the point of operation. In addition, this chapter guides you through the
installation of Trio, the communications software included with your modem.
Chapter 3 - Software Configuration and Modem Basics
Chapter 3 documents communication software configuration recommended specifically for the
MultiModem. Other issues covered include setting up initialization strings, changing default
parameters, configuring software for the remote system and file transfer protocols.
Chapter 4 - Manual Dial and Automatic Answer
Chapter 4 covers some modem operations, but delays discussion on Command Mode operation until
Chapter 5. Automatic Leased Line Restoration, Dial backup, Manual Dial Mode, and Answer Mode
operation are covered in detail, as well as the handshaking procedures employed between two
modems in an auto-answer application.
8
Chapter 1 - Introduction and Description
Chapter 5 - AT Command Mode Operation
Chapter 5 may be the most important chapter of this manual. It begins with an introduction and
discussion on Command Mode fundamentals. A flow chart is provided to illustrate Command Mode
and On-Line Mode operation and the methods used in each mode. Next, there is a summary of the
modem’s commands and responses. We then go into a detailed explanation of each modem
command, providing examples where applicable.
Chapter 6 - S-Registers
Chapter 6 covers the modem's S-Registers, which enable the user to establish, read, and modify
various modem options. All of the S-Registers are charted and explained, followed by instructions on
accessing the S-Registers and reading or changing their values.
Chapter 7 - Callback and Remote Configuration
Chapter 7 documents instructions on how to operate the modem's Callback and Remote
Configuration features; and the usage of LOGIN Passwords, Set-Up Passwords and Remote Escape
Characters as network management tools.
Chapter 8 - Testing Your Modem
Chapter 8 covers the modem's built-in test features. These are: Power-on Self Test, Back-To-Back
Test, Local Analog Loopback, Digital Loopback and Remote Digital Loopback Tests. We have
included a description of each test and how to use each test procedure.
Chapter 9 - DIP-Switches
Chapter 9 covers the modem’s printed-circuit board options. Sixteen DIP-Switch settings and the
modem's speaker volume control are explained in detail, including all default settings.
Chapter 10 - Warranty, Service & Technical Support
Chapter 10 provides statements on your five-year warranty, instructions for getting modems serviced
at the factory, the procedure for downloading firmware upgrades via FlashROM, information about
Multi-Tech's Bulletin Board Service (BBS), a section on receiving technical support via the
CompuServe/Internet forums and information on Multi-Tech's Fax-Back Service.
Appendixes
There are also several appendices at the end of this manual, most of which repeat information
contained in the chapters, but in a more condensed form. These appendices can be used as a quick
reference.
Appendix A - Troubleshooting
Appendix B - ASCII/HEX/Decimal Conversion Chart
Appendix C - Pulse Dial and Tone-Dial Frequencies
Appendix D - AT Command Summary
Appendix E - DIP Switch Summary
Appendix F - S-Register Summary
Appendix G - Result Code Summary
Appendix H - V.25bis Operation
Appendix I - Cabling Diagrams
Appendix J - RS-232 Interface Specifications
Appendix K - Regulatory Information
9
MultiModemBL User Guide
1.3 Modem Features
The MultiModem BL Series modem connections can be made on Public Switched Telephone
Networks (PSTNs) and/or point-to-point 2-wire and 4-wire leased telephone type circuits.
Your modem offers interactive automatic dialing, as well as Command Mode option configuration.
You may store up to ten command line/telephone numbers, of up to 60 characters each, in the
modem’s nonvolatile memory. The modem pulse or tone dials, and recognizes dial tones and busy
signals for reliable call-progress detection. The modem can detect AT&T calling card tones. It is
FCC-Registered for connection to telephone networks without any Data Access Arrangements
(DAA’s).
Your modem also features Callback Security to protect networks from unauthorized use, and to
manage phone line costs. By using the modem’s phone number and password directory, a host site
can, upon receipt of a call, callback to a remote site at a predetermined number.
Remote Configuration permits you to assist users at remote sites, saving you the time and trouble of
site visits and preventing misinterpretation of configuration instructions.
1.3.1 2834 Series Features
Your MT2834BL modem meets the proposed Enhanced V.34 ITU standard for data signalling rates
as high as 33.6/31.2K bps in full duplex mode. Enhanced V.34 is an extension of V.32/V.32bis/V34
standards, and supports and is compatible with those features, including EIA extended Automode;
adaptive line probing; automatic symbol rate and carrier frequency during start-up; and retrain and
rate renegotiation (in 2400 bps increments).
The major application for the MT2834BL is in 4-wire leased line networks with the addition of dial
backup capability. With this capability, the dial-up feature saves any down time if the leased line fails.
Since the MT2834BL operates according to ITU V.34 modulation, it can operate full-duplex over two
wires, so that the dial backup mode performs the same throughput as the leased line.
The MT2834BL features ITU V.42 error correction and V.42bis data compression, providing 100%
error-free data transmission. V.42 error correction incorporates MNP( Classes 3 and 4, and LAP-M.
You may select V.42bis data compression for 4-1 throughput, or MNP Class 5 for 2-1 throughput.)
1.3.2 1932 Series Features
Your MT1932BL modem is designed according to the American Telephone and Telegraph (AT & T)
V.32terbo de facto standard for data signalling rates as high as 19.2/16.8K bps full-duplex mode.
V.32 terbo supports and is compatible with all V.32 and V.32bis features including EIA extended
Automode, the V.32 start-up sequence, and V.32bis retrain and rate renegotiation.
The major application for the MT1932BL is in 4-wire leased line networks with the addition of dial
back-up capability. With this capability, the dial-up feature saves any down time if the leased line
fails.
The MT1932BL is AT command set compatible and incorporates a number of capabilities beyond the
basics of V.32terbo operation. Other capabilities include CCITT V.25bis standard for synchronous
dialing, compatibility with CCITT V.42 error correction and V.42bis data compression in which data
communication speeds can approach 78,600 bps (depending on the file content and the receiving
modem’s capability) and the data sent will be 100% error free. V.42 error correction incorporates both
MNP Classes 3, 4 and LAPM. Data compression can be V.42bis for 4 to 1 throughput improvement
or MNP Class 5 for 2 to 1 throughput.
10
1.3.3 1432 Series Features
Your MT1432BL modem is designed according to the international CCITT V.32bis specification for
data signalling rates as high as 14.4K bps in full-duplex mode.
The major application for the MT1432BL is in 4-wire leased line networks (replacing traditional V.29/
9600 bps & V.33/14,400 bps modems) with the addition of dialback-up capability. With this
capability, the dial-up feature saves any down time if the leased line fails. Since the MT1432BL
operates according to CCITT V.32bis modulation, it can operate full-duplex over two wires, so that
the dial back-up mode performs the same throughput as the leased line.
The MT1432BL is AT command set compatible and incorporates a number of capabilities beyond the
basics of V.32bis operation. Other capabilities include CCITT V.25bis synchronous dialing,
compatibility with CCITT V.42 error correction and V.42bis data compression in which data
communication speeds approach 57,600 bps (depending on the file content and the receiving
modem’s capability) and the data sent will be 100% error free.
1.4 Fax Features
Your modem meets the ITU V.17 standard for sending and receiving faxes. When linked to a
compatible fax machine or modem, it can transmit faxes at 14,4 K bps. It also meets the ITU’s Group
3 Designation for sending and receiving faxes at 9600 bps; and Group 2 Designation for sending and
receiving faxes at 4800 bps. The modem is also downward-compatible with modems to speeds as
low as 300 bps, so it can send and receive faxes with any fax machine in the world.
Chapter 1 - Introduction and Description
11
MultiModemBL User Guide
1.5 Technical Specifications
Your data/fax modem meets the specifications listed below:
Tradename MultiModem
Model Numbers
2834 Series: MT2834BL, MT2834BLI, MT2834BLK
1932 Series: MT1932BL, MT1932BLI, MT2834BL-MAC
1432 Series: MT1432BL, MT1432BLI, MT21432BLK
Data Rates (modem)
2834 Series: 33,600, 31,200, 28,800, 26,400, 24,000, 21,600, 19,200, 16,800,
14,400, 12,000, 9600, 7200, 4800, 2400, 1200, 0-300 bps
1932 Series: 19,200, 16,800, 14,400, 12,000, 9600, 7200, 4800, 2400, 1200,
0-300 bps
1432 Series: 14,400, 12,000, 9600, 7200, 4800, 2400, 1200, 0-300 bps
Data Rates (fax)
All Models: 14,400, 9600, 7200, 4800 bps
IITM
Data Format
2834 Series: Serial, binary, asynchronous at 0-300, 1200, 2400, 4800, 7200,
9600, 12,000, 14,400, 16,800, 19,200, 21,600, 24,000, 26,400,
28,800, 31,200, 33,600 bps; synchronous at 1200, 2400, 4800,
7200, 9600, 12,000, 14,400, 16,800, 19,200, 21,600, 24,000, 26,400,
28,800, 31,200, 33,600 bps
1932 Series: Serial, binary, asynchronous at 0-300, 1200, 2400, 4800, 7200,
9600, 12,000, 14,400, 16,800, 19,200 bps; synchronous at 1200,
2400, 4800, 7200, 9600, 12,000, 14,400, 16,800, 19,200 bps
1432 Series: Serial, binary, asynchronous at 0-300, 1200, 2400, 4800, 7200,
9600, 12,000, 14,400 bps; synchronous at 1200, 2400, 4800, 7200,
9600, 12,000, 14,400 bps
Compatibility
2834 Series: ITU V.42bis, V.42, Pending ITU Enhanced V.34 approval, ITU V.34,
ITU V.32bis, V.32, V.21*, V.22bis, V.22, V.23*,V.25bis, *Bell 212A
and 103/113, ITU V.17, Group 3 T.4, T.30 and EIA TR-29 Class 2
(*Bell 212A and 103/113 domestic models only; *V.21/V.23 Int'l
models only)
1932 Series: CCITT V.42bis, V.42, AT&T V.32terbo, CCITT V.32bis, V.32, V.21*,
V.22bis, V.22, V.23*, V.25bis, Bell 212A and 103/113, CCITT V.17,
Group 3 T.4, T.30 and EIA TR-29 Class 2 (* V.21/V.23 Int’l models
only)
1432 Series: CCITT V.42bis, V.42, CCITT V.32bis, V.32, V.21*, V.22bis, V.22,
V.23*, V.25bis, Bell 212A and 103/113*, CCITT V.17, Group 3 T.4,
T.30 adn EIA TR-29 Class 2 (* Bell 212A and 103/113 domestic
models only; * V.21/V.23 Int’l models only)
12
Error Correction
All models: V.42 (LAP-M or MNP 3 & 4) error correction
Chapter 1 - Introduction and Description
Data Compression
All models: V.42bis, (4:1 throughput) or MNP 5 (2:1 throughput) data
compression
Speed Conversion
2834 and 1932 Series: Serial port data rates adjustable to 300, 1200, 2400, 4800, 9600,
19,200, 38,400, 57,600 and 115,200 bps
1432 Series: Serial port data rates adjustable to 300, 1200, 2400, 4800, 9600,
19,200, 38,400, and 57,600 bps
Flow Control Options
All models: Xon/Xoff, Hardware RTS/CTS, ENQ/ACK, Unix-to-Unix Copy
Protocol (UUCP) "Spoofing"
Mode of Operation
All models: Full duplex over both dial-up lines and 2- or 4-wire leased lines;
automatic Dial backup on separate lines in leased line operation;
automatic or manual dialing, automatic or manual answer
Intelligent Features
All models: Fully “AT command” compatible, microprocessor controlled remote
configuration, EIA extended Automode, adaptive line probing,
automatic symbol rate and carrier frequency during start-up, retrain
and rate renegotiation, autodial, redial, repeat dial, dial linking, pulse
or tone dial, dial tone detection, dial pauses, call status display, autoparity and data rate selection, keyboard-controlled modem options,
nonvolatile memory and on-screen displays for modem option
parameters and up to ten telephone numbers/command lines of up
to 60 digits each, help menus
Command Buffer
All models: 60 characters
Modulation
2834 Series: Trellis Coded Modulation (TCM) at 33,600, 31,200, 28,800, 26,400,
24,000, 21,600, 19,200, 16,800, 14,400, 12,000 and 9600 bps,
Quadrature Amplitude Modulation (QAM) at 9600 (non-trellis), 4800
and 2400 bps, PSK at 1200 bps, FSK at 300 bps
1932 Series: Trellis Coded Modulation (TCM) at 19,200, 16,800, 14,400, 12,000
and 9600 bps, Quadrature Amplitude Modulation (QAM) at 9600
(non-trellis), 4800 and 2400 bps, PSK at 1200 bps, FSK at 300 bps
1432 Series: Trellis Coded Modulation (TCM) at 14,400, 12,000 and 9600 bps,
Quadrature Amplitude Modulation (QAM) at 9600 (non-trellis), 4800
and 2400 bps, PSK at 1200 bps, FSK at 300 bps
Fax Modulations
All models: V.21CH2 FSK at 300 bps, V.27ter DPSK at 4800 and 2400 bps,
V.29 QAM at 9600 and 7200 bps, V.17 TCM at 14400, 12000, 9600,
and 7200 bps
13
MultiModemBL User Guide
Fax Carrier Frequencies
All models: V.21CH2 (Half Duplex)
Lease Line Restoral
All models: When in dial backup mode, modem attempts leased line restoral
Carrier Frequencies
2834 Series: 1800 Hz V.32/V.32bis/V.34/Enhanced V.34--33.6K/31.2K/28.8K/
1932 Series: 1800 Hz V.32/V.32bis/V.32terbo/19.2K/16.8K/14.4K/12K/9.6K/7.2K/
1432 Series: 1800 Hz V.32/V.32bis/14.4K/12K/9.6K/7.2K/4.8K
Carrier Frequencies - 2400 & 1200 bps (V.22bis/V.22 or Bell 212A Standard)
1650Hz Mark, 1850Hz Space for Transmit Originate
1650Hz Mark, 1850Hz Space for Transmit Answer
V.27ter 1800Hz Originate/Answer
V.29 QAM 1700Hz Originate/Answer
V.17 TCM 1800Hz Originate/Answer
periodically (controlled by S-Register S18 setting)
26.4K/24K/21.6K/19.2K/16.8K/14.4K/12K/9.6K/7.2K/4.8K
4.8K
All models: Transmit Originate: 1200 Hz
Transmit Answer: 2400 Hz
Receive Originate: 2400 Hz
Receive Answer: 1200 Hz
Carrier Frequencies - 300 bps (Bell Standard)
All models: 1270 Hz Mark, 1070 Hz Space for Transmit Originate
2225 Hz Mark, 2025 Hz Space for Receive Originate
2225 Hz Mark, 2025 Hz Space for Transmit Answer
1270 Hz Mark, 1070 Hz Space for Receive Answer
Carrier Frequencies - V.21
All models: 980 Hz Mark, 1180 Hz Space for Transmit Originate
1650 Hz Mark, 1850 Hz Space for Transmit Answer
650 Hz Mark, 1850 Hz Space for Receive Originate
980 Hz Mark, 1180 Hz Space for Receive Answer
Carrier Frequencies - V.23
All models: 390 Hz Mark, 450 Hz Space for Transmit Originate
1300 Hz Mark, 2100 Hz Space for Transmit Answer
1300 Hz Mark, 2100 Hz Space for Receive Originate
390 Hz Mark, 450 Hz Space for Receive Answer
Transmit Level
14
All models: -11dBm (dial-up), -9 or -15 dBm (leased-line); dBm level selectable
with DIP-Switch #3 in leased line setting; -10dBm (dial-up)*, -13 dBm
(leased-line)*
*BLK models Only
Frequency Stability
All models: ±0.01%
Chapter 1 - Introduction and Description
Receiver Sensitivity
All models: -43 dBm under worst case conditions
AGC Dynamic Range
All models: 43 dB
Interface
All models: EIA RS-232C/ITU V.24
Connectors
BL models: One DB-25 RS-232C connector; three RJ11 for phone line, dial-up
and leased line; power.
BLK models: One DB-25 RS-232C connector; two BT plugs for dial-up and leased
line; power
Diagnostics
All models: Power-on Self Test, Local Analog Loop, Local Digital Loop, Remote
Digital Loop, Back-to-Back Test.
Indicators
All models: LEDs for Transmit Data, Receive Data, Carrier Detect, Speed
Indicators, Off Hook, Terminal Ready, Error Correction, Fax, and
Error
Controls
All models: Toggle switches for Voice/Data with Originate or Answer, Power On/
Off; and DIP Switches for various modem options.
Speaker
All models: Speaker for call progress monitoring
Operating Temperature
All models: 0° to 50° C (32° to 120° F)
Power Requirements
All models: 115 Volts AC, 60Hz, 0.3amp (2-prong outlet-mounted transformer)
240V/50Hz optional (International).
Dimensions
All models: 6.150" x 9.00" x 1.375"
15.6 cm x 22.9 cm x 3.5 cm
Weight
All models: 1.6 pounds/0.72 Kg (without transformer)
2.6 pounds/1.18Kg (with transformer)
Limited Warranty
All models: Five Years
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MultiModemBL User Guide
1.6 Power
Power is supplied through an AC power transformer terminated with a standard two-prong plug. The
transformer supplies low voltage AC to the modem, and plugs into any conventional 115 volt AC, 60
Hz, two-prong power outlet (240 volts AC, 50Hz, .3 Amp for International modems). The power
transformer supplied with the modem is the only one that should be used. Use of any other
transformer could cause damage to the modem. A Power On/Off switch is located on the back of the
modem.
1.7 Modem LED Indicators
The MultiModem diagnostic LED indicators are shown in Figures 1-1a, 1-1b, and 1-1c.
Figure 1-1a. MT2834 LED Display
Figure 1-1b. 1932 LED Display
Figure 1-1c. MT1432 LED Display
(SD) Send (Transmit) Data. This LED blinks when data is being transmitted, on for a space, off for a
mark. The state of this LED matches the TD circuit on Pin 2 of the RS-232C/V.24 interface.
(RD) Receive Data. This LED blinks when data is being received, on for a space, off for a mark. The
state of this LED matches that of the RD circuit on Pin 3 of the RS-232C/V.24 interface.
(CD) Carrier Detect. This LED is lit when a valid carrier tone has been detected.
2834 Models Only:
When the modem is connected at 33,600 bps, the 28.8 LED rapidly blinks at approximately 5
blinks per second.
When the modem is connected at 31,200 bps, the 28.8 LED blinks slowly at approximately 1
blink per second.
16
(28.8) 28,800 bps. (2834 models only) This LED is lit when the modem is connected at 28,800 bps.
Note: if the modem falls back to 26.4K bps while in V.34 mode, both the 28.8 and 24.0 LEDs light.
Chapter 1 - Introduction and Description
(24.0) 24,000 bps. (2834 models only). This LED is lit when the modem is connected at 24,000 bps.
Note: if the modem falls back to 21.6K bps while in V.34 mode, both the 24.0 and 19.2 LEDs light.
(19.2) 19,200 bps. (2834 and 1932 models only) This LED is lit when the modem is connected at
19,200 bps.
(14.4) 14,400 bps. This LED is lit when the modem is connected at 14,400 bps. Note: if the modem
falls back to 12,000 bps while in V.32bis mode, both the 14.4 and 96 LEDs light.
(96) 9600 bps. This LED is lit when the modem is connected at 9600 bps.
(24) 2400 bps. This LED is lit when the modem is connected at 2400 bps.
(12) 1200 bps. (1432 models only) This LED is lit when the modem is connected at 1200 bps.
(OH) Off Hook. This LED is lit when the phone line is "off hook". This occurs when the modem is
dialing, on-line, or answering a call. This LED also flashes when the modem is pulse dialing in
Command mode.
(TR) Terminal Ready. When the TR LED is lit, the modem is permitted to answer an incoming call.
When it goes off, a connected modem will disconnect. The state of the TR LED matches that of the
DTR circuit on Pin 20 of the RS-232C/V.24 interface.
(EC) Error Correction. This LED is lit when the modem is set for V.42 error correction, and flashes on
and off when data compression is activated.
(FX) FAX. This LED is lit when the modem is connected in FAX mode.
(ERR) ERROR. When this LED is lit, either the leased line is down and the modem is in dial backup
mode, or else the self-test has failed.
1.8 Controls on PC Board
The MultiModem is designed on a single printed circuit (PC) board. This board contains one 16position DIP-Switch (numbered 1-16). The DIP-Switches are accessible through a cut-out on the side
of the modem. There is also a knob which is used to adjust the speaker volume. This knob is
accessible through the modem's rear panel. The sixteen DIP-Switches control various modem
options or set default values for Command Mode operation. There is a difference in how several of
the switches operate depending on whether you are in synchronous or asynchronous mode. Refer to
the switch label on the bottom of the modem for an exact list of the switch functions in asynchronous
and synchronous operation. Chapter 9 of this manual also provides detailed instructions on
configuring all of the modem's PC board options.
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MultiModemBL User Guide
18
Chapter 2 - Installation and Connection
MultiModemBL User Guide
2.1 What is in Your Modem Package?
Your MultiModem is made up of many components. Make sure you have them all before trying to
operate your modem.
MADE IN U.S.A
MADE IN U.S.A
Figure 2-1. Unpacking (MT2834BL shown)
Your package should include:
• MT2834BL, MT1932BL or MT1432BL data/fax modem
• RJ-11 telephone cord or BS-6312 Plug (UK models)
• AC Power Transformer
• One (1) Quick Start Guide
• One (1) software CD (TrioTM data communications and fax software)
• This User Guide (on diskette)
If any of these items are missing, please refer to the Chapter 10 for information on contacting Tech
Support.
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2.2 Installation
The installation of the modem consists of making the physical connections necessary to render the
modem functional with your computer. This includes making the proper serial, phone line, and power
connections. Unless otherwise noted, these instructions apply to all models of the BL series.
2.2.1 Safety Warnings
1 Never install telephone wiring during a lightning storm.
2 Never install telephone jacks in wet locations unless the jack is specifically designed for wet
locations.
3 Never touch uninsulated telephone wires or terminals unless the telephone line has been
disconnected at the network interface.
4 Use caution when installing or modifying telephone lines.
5 Avoid using a telephone (other than a cordless type) during an electrical storm. There may be a
remote risk of electrical shock from lightning.
6 Do not use the telephone to report a gas leak in the vicinity of the leak.
7 Ports which are connecting to other apparatus are defined as SELV. To ensure conformity with
EN 41003, ensure that these ports are only connected to the same type on other apparatus.
Chapter 2 - Installation and Connection
2.2.2 Installation Procedure
The following procedures will guide you through the physical connections required to make your
modem operational. Software loading is covered later in this guide.
Note: There are two procedures in this section. The first details cabling for domestic (BL) and
international (BLI) models. The second details cabling for BABT (BLK) models only. Please follow the
procedure that matches your model.
2.2.3 Cabling Procedure (MT1432BL/BLI, MT1932BL/BLI, and
MT2834BL/BLI)
Step Procedure
1 Verify that the settings for DIP-Switch #5 and DIP-Switch #10 match those of your system
configuration.
The 16-position DIP-Switch (numbered 1-16) is accessible through a cut-out on the right side (as
the LEDs are facing you) of the modem chassis. For a full description of all DIP-Switch Settings,
refer to Chapter 9.
DIP-Switch Condition Effect
#5 UP* Selects Answer mode
DOWN Selects Originate mode
#10 UP* Selects Dial-Up operation
DOWN Selects Lease Line operation
* indicates Factory Default setting
2 Verify that the ON/OFF switch at the rear of the modem to the OFF (Down) position.
3 Connect the modem to either a dial-up line or lease-line.
To connect the modem to a dial-up phone line, attach the RJ-11 telephone cord (provided with
your unit) to the PSTN connector on the modem and to a dial-up wall jack. Refer to Figure 2-2.
To connect the modem to a leased line, attach the RJ-11 telephone cord (provided with your unit)
to the LEASE connector on the modem and to a leased line wall-jack. Refer to Figure 2-2.
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MultiModemBL User Guide
PHONE PSTN
LEASE
VOLUME
EIA RS232C
POWER
ON
OFF
Figure 2-2. MultiModemBL/BLI Connections
4 Attach the EIA RS-232C connector on the modem to the serial port on your computer or terminal
with an RS-232 (or V.24) cable (you supply). Refer to Figure 2-2.
5 To connect a telephone set to the modem (optional) plug one end of an RJ-11 phone cord into
the PHONE connector on the modem, and plug the other end into your telephone. Refer to
Figure 2-2.
6 Attach the AC Power transformer provided with your unit to the POWER connector on the
modem and to a live AC outlet. Refer to Figure 2-2.
Note: Only apply power to the modem using the power transformer provided with your unit. Use
of a power supply not designed for your unit could result in damage to your modem and will void
the warranty.
7 Apply power to the unit by setting the ON/OFF switch at the rear of the modem to the ON (Up)
position. Refer to Figure 2-2.
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Chapter 2 - Installation and Connection
2.2.4 Cabling Procedure (MT1432BLK and MT2834BLK)
Step Procedure
1 Verify that the settings for DIP-Switch #5 and DIP-Switch #10 match those of your system
configuration.
The 16-position DIP-Switch (numbered 1-16) is accessible through a cut-out on the right side (as
the LEDs are facing you) of the modem chassis. For a full description of all DIP-Switch Settings,
refer to Chapter 9.
DIP-Switch Condition Effect
#5 UP* Selects Answer mode
DOWN Selects Originate mode
#10 UP* Selects Dial-Up operation
DOWN Selects Lease Line operation
* indicates Factory Default setting
Note 1: BLK models use pins 1 and 6 of the BS-6312 plug for two-wire lines. For four-wire lines,
the modems use pins 1 and 6 to transmit and pins 2 and 5 to receive.
Note 2: BABT regulations require that telecommunication cables must be connected to the
modem prior to being connected to the network.
2 Verify that the ON/OFF switch at the rear of the modem to the OFF (Down) position.
3 Connect the modem to either a dial-up line or lease-line.
To connect the modem to a dial-up phone line, attach the BS-6312 telephone cord (provided with
your unit) to the PSTN connector on the modem and to a dial-up wall jack. Refer to Figure 2-3.
To connect the modem to a leased line, attach the BS-6312 telephone cord (provided with your
unit) to the LEASE connector on the modem and to a leased line wall-jack. Refer to Figure 2-3.
PSTN
LEASE
VOLUME
EIA RS232C
ON
OFF
POWER
Figure 2-3. MultiModemBLK Connections
4 Attach the EIA RS-232C connector on the modem to the serial port on your computer or terminal
with an RS-232 (or V.24) cable (you supply). Refer to Figure 2-3.
5 Attach the AC Power transformer provided with your unit to the POWER connector on the
modem and to a live AC outlet. Refer to Figure 2-3.
Note: Only apply power to the modem using the power transformer provided with your unit. Use
of a power supply not designed for your unit could result in damage to your modem and will void
the warranty.
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MultiModemBL User Guide
2.3 Loading Trio DataFAX Software
The following procedure will guide you through the installation of Trio DataFAX software. The
procedure does not provide every screen or option in the process. The installation utility provides onscreen instructions for those elements that are not covered in this procedure. If you encounter
problems during installation, refer to the Release Notes included on the Trio CD.
1 Turn on your computer and insert the Trio CD into your CD-ROM drive. If you have autorun
enabled, the Trio welcome screen will appear. If autorun is disabled, you can start the installation
program by clicking double-clicking Setup16 or Setup32 from the root directory of the Trio CD.
2 Click the Next (
language and click Next to proceed.
3 Click Next to proceed with the default country, United States, or select the country in which you
are installing and click Next to proceed. The Trio Welcome screen is displayed
Note: If you have a sound card installed on your computer and wish to turn off the music portion
of the Trio CD, you can click the Speaker ( ) icon to turn the sound off. Click Speaker again to
turn it back on.
4 Click Next. The following dialog is displayed:
5 Click Trio... to continue. The following dialog box is displayed
) icon to proceed with the default language, English, or select the desired
24
6 Click Install Trio... to continue. The Select Language dialog is displayed.
7 Click OK to proceed with the default language, English, or select the desired language from the
drop-down list and click OK. The License Agreement dialog is displayed.
8 Read the license agreement, and click OK when you are finished. You are prompted to read
important information.
Chapter 2 - Installation and Connection
9 Click Yes to read the Release Notes. when you are finished, close the release notes dialog and
the Trio Setup dialog is displayed.
10 Click Complete Installation and the installation introduction is presented.
11 Click Next Dialog and follow the on-screen instructions to load the software.
Once the software has finished loading, the following dialog is displayed:
12 Choose Manual Selection of Modem and Ports, then click Next Dialog. The following dialog is
displayed:
13 In the Com Port Selection group select the COM port, on which your modem is installed, from
the drop-down list.
14 In the Modem Type group select Class 2 Compatible from the drop-down list.
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MultiModemBL User Guide
15 Click Next Dialog. The Phone Numbers and Prefixes dialog is displayed.
16 Follow the on-screen instructions and when you are finished, click Next Dialog. The following
dialog is displayed:
17 Click OK, Exit the Installation Program. The Trio Applications program group is displayed.
Your Trio software is loaded. If you wish to begin using Trio right away, double click on the Trio
DataFax Voice icon. Refer to the Release Notes for instructions.
To quit Trio altogether, close the Trio Applications program group, and then click the Exit ( ) icon
on the installation screen to exit the installation program.
2.4 Is Your Modem Ready for Use?
As soon as you have connected power to the modem, if you are an experienced modem user, you
may simply want to check your modem’s settings for data compression, error correction, and so on.
You may find that you can get moving quite quickly if you just issue an ATL5, ATL6 and an ATL7
command. These commands list how your modem is currently configured. If you come across a
setting you’re unsure of, refer to Chapter 5 and Chapter 6 for AT command and S-Register
explanations and defaults.
If you’re a novice, refer to Chapter 3 to learn about the basics of data communications.
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Chapter 3 - Software Configuration and Modem Basics
MultiModemBL User Guide
3.1 Introduction
Chapter 2 guided you through the installation of Trio communications software. If you are using a
different software package, there are some points you should take into consideration. Since your
communications software configuration is affected by the capabilities of your computer, this chapter
begins with a discussion of the limitations of some serial ports and how to identify them. It then
discusses communications configuration in general and recommends settings specifically for the
MultiModem. The last section of this chapter walks you through the basics of using your modem.
3.2 Serial Port Limitations
When you configure your software, you need to consider how the hardware on both ends of the
connection will affect the connection. Some serial ports, particularly those in older PC-compatible
computers, may limit the performance of the modem. You should know if yours is one of them.
The limiting factor is an integrated circuit called a Universal Asynchronous Receiver/Transmitter, or
UART. All data from your modem flows through it. The UARTs typically used in PC-compatible
computers are types 8250, 8250A, 16450, and 16550AFN. The 8250 is unreliable above 9,600 bps,
and the 8250A and 16450 are unreliable above 19,200 bps. If the modem sends data to the UARTs
above those speeds, the UARTs may not be able to process the data fast enough to keep from losing
some of it. The 16550AFN, however, can safely handle data to 115,200 bps.
When a modem communicates with V.42bis 4-to-1 compression enabled, it sends up to four times as
much uncompressed data to the serial port as it receives compressed over the telephone line.
Therefore, a modem communicating at 14,400 bps may require a serial port that can reliably transfer
data at four times 14,400 bps, or 57,600 bps; at 19,200 bps it may require one that works reliably up
to four times 19,200 bps, or 76,800 bps; and at 28,800 and 33,600 bps it may require one that works
reliably up to a maximum of 115,200 bps. If your serial port cannot handle these speeds, we
recommend that you replace your present serial card with one that has a 16550AFN UART or
equivalent.
Macintosh computers do not use UARTs. The Macintosh SE through IIfx models use a Zilog Z8530
chip called a Serial Communications Controller, or SCC, that has a maximum speed of 57,600 bps.
This speed can be compromised by other serial communications, including printer transmissions and
Appletalk, the networking software that allows Macintoshes to share files. When Appletalk is active it
controls all serial communications on the Macintosh. Because it gives priority to network
communications, it may lose modem data at higher transmission speeds. Therefore, when Appletalk
is active you risk losing data on serial port communications over 2400 bps, though most users can
work up to 9600 bps without problems. Other activities that could cause the serial driver to drop bits
at high speeds include the floppy disk driver formatting a disk, the CPU paging in or out in virtual
memory mode, and the Mac IIci or IIsi running the on-board video in 8-bit mode. Therefore, for
maximum communications speed on the Macintosh, we recommend as few concurrent activities as
possible. To use V.42bis compression at 19,200 bps or faster, we recommend that you install a high
speed serial port card. Newer Macintosh computers, such as the Quadra and Centris models,
support serial port speeds up to 115,200 bps.
3.2.1 How Can You Identify Y our UART Type?
28
If you have MS-DOS 6.0 or later, you can find your UART type from a diagnostic program called
MSD. To use it, type MSD at the DOS prompt. After the opening screen, select COM Ports.... The
last line of the report tells you what type UART you have for each COM port. MSD does not
distinguish between the 8250 and the 8250A. However, if you have an IBM AT or newer computer,
you likely have an 8250A or 16450 UART installed, both of which are reliable to 19,200 bps. If you
would like more detailed information about your UART than MSD can provide, you can download
shareware UART identification programs from the IBM Communications Forum on CompuServe, or
from a local BBS.
Chapter 3 - Software Configuration
3.2.2 The 16550 UART and Windows 3.1
Windows 3.1 may cause a loss of data when communicating at high speed, even with a 16550 UART
installed. Because Windows is multitasking—it switches between several programs running at the
same time—it can make the serial port wait briefly while Windows performs other tasks. Meanwhile,
incoming data can be lost. The older 8250A and 16450 UARTs can store data in a one-byte first infirst out (FIFO) buffer (a memory area in the UART in which the first bit in is the first out), but once
the buffer is full, the data is lost. The 16550 has a 16-byte FIFO buffer, which accounts for much of its
high speed. However, in Windows 3.1, the 16550’s FIFO buffer is disabled by default. To enable the
buffer, use Notepad to open the SYSTEM.INI file in your Windows directory, and add the following
line to the [386Enh] section:
COMnFIFO=1
where n is the number of the COM port the 16550 is installed on. For example, if the 16550 is
installed on COM2, the line should be:
COM2FIFO=1
After you save SYSTEM.INI you must restart Windows for the change to take effect.
However, there is another problem when the FIFO buffer is enabled: Windows cannot recognize the
COM port because of a bug in the Windows 3.1 serial port driver, COMM.DRV. The only way around
this problem is to replace the COMM.DRV file in the WINDOWS\SYSTEM directory with another
driver. Several drivers are available commercially or on BBSs that will solve this problem. A freeware
driver called CyberCom is available as CYBERC.ZIP on CompuServe in the IBM Communications
Forum, Library 0. CyberCom will enable Windows communications at speeds up to 115,200 bps if
you have a 16550 UART installed.
3.3 Configuring Your Software
Communications software must be configured to work with your modem, your computer, and the
remote system it is calling. Fortunately, most communications programs make the process easy by
providing a default initialization string for your modem as well as defaults for most of the other
required parameters.
3.3.1 Configuring Software for Your Modem
Because remote computers may have different connection requirements such as speed, number of
bits, parity, log-on sequences, etc., communications software is typically configured by sessions,
each session having a unique configuration for a given connection (e.g., to a BBS or commercial online service). Most communications programs, however, have a separate modem configuration menu
because modem configurations rarely change from session to session.
The most important configuration is the modem initialization string. This is a sequence of commands
the software uses to configure the modem when the communications software is loaded or when a
session begins. Always begin the initialization string with the ATtention command AT, then follow it
with the modem reset command, &F. Issuing a reset command before other commands ensures that
you are starting with a known state.
The rest of the commands in the initialization string depend on the capabilities of the modem and
what you want it to do. Some older communications programs require you to create the initialization
string by yourself. Most modern communications programs, however, provide you with a ready-made
initialization string that is automatically selected when you choose your modem model from a list. It is
a poor idea to use an initialization string intended for another modem, especially one from another
manufacturer, because modem capabilities and command implementations vary from modem to
modem. However, if your MultiModem does not appear on a modem list, you may use the
MultiModemII initialization string.
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MultiModemBL User Guide
3.4 PC Initialization Strings
We recommend the following initialization string for a MultiModem connected to a PC-compatible
computer when sharing a line with a telephone:
AT &F X4 S0=0 ^M
This string resets the modem to the factory default settings, selects extended result codes with NO
DIAL TONE and BUSY, and turns off auto-answer. ^M must end every string sent to the modem from
software. It is the ASCII code for the RETURN key on most keyboards, and the default code for the
carriage return character in the modem and most communications programs. The carriage return
character is defined in the modem in S-register S3; if you change it, you must also change the
carriage return character code used in your communications software. If you send a command
directly to the modem in terminal mode rather than indirectly through communications software, you
must end the command string by pressing the RETURN key (<CR>) instead of adding ^M to the
string.
The following initialization string is for a MultiModem on a telephone line that functions solely as a
DATA LINE:
AT &F X4 S0= 2 ^M
3.4.1 Changing Default Parameters
By default, the modem will answer after the first ring and try to communicate with a modem on the
other end of the line. If you have one telephone line for voice, fax, and modem communications, the
modem may attempt to answer all incoming calls, voice as well as data. To change auto-answer to
default off, open your communications program and type the following string in the terminal window:
AT &F S0=0 &F9 &W0 <CR>
This string selects the factory default parameters, then turns auto-answer off and stores that setting,
along with all other current parameters, in nonvolatile memory. The &F9 command causes the
modem to load the values from nonvolatile memory the next time it receives the &F command. You
will use the same initialization string as before:
AT &F X4 ^M
But now the modem will load the values stored in nonvolatile memory when you turn on the modem
and when you issue the ATZ or AT&F reset commands.
Note: Because it clears the command buffer, you should not use ATZ in an initialization string.
3.4.2 Other Parameters
The default values for the other parameters in modem configuration menus rarely need changing.
They typically include the dialing prefix (ATDT for touch-tone service and ATDP for rotary service),
the dialing suffix (^M), the hang-up string (+++ATH0^M), and response messages (RING, NO
CARRIER, BUSY, etc.). Communications software with a host mode might also include an autoanswer string (AT S0=1^M).
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