Multitech CommPlete MT3334HD8 User manual

MT3334HD8 Modem
User Guide

MT3334HD8 User Guide
P/N 82063701, Revision B
Copyright © 1997 by Multi-Tech Systems, Inc.
All rights reserved. This publication may not be reproduced, in whole or in part, without prior expressed
written permission from Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representation 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.
Revision Date Description
A
B
3/31/97
5/29/97
Manual released.
Manual updated.
Multi-Tech, CommPlete, RASExpress, MultiExpress, MultiExpress Fax MultiModem, MultiModemZDX,
MultiModemManager, and the Multi-Tech logo are trademarks of Multi-Tech Systems, Inc. Other
trademarks and trade names mentioned in this publication belong to their respective owners.
Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112
[phone] or [phone]
U.S. Fax [phone]
Technical Support [phone] or Email to: [email protected]
Internet Address: http://www.multitech.com

CommPlete Communications Server iii
Federal Communications Commission Statement
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant
to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy, and if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio 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.
Warning: Changes or modifications to this unit not expressly approved by the party responsible for
compliance could void the user’s authority to operate the equipment.
FCC Regulations for Telephone Line Interconnection
1. No repairs are to be made by you. Repairs are to be made only by Multi-Tech Systems or its
licensees. Unauthorized repairs void registration and warranty. Contact Multi-Tech Systems, Inc. for
details of how to have repairs made.
2. When trouble is experienced, you must disconnect your modem from the telephone company’s jack
to determine the cause of the trouble, and reconnect your modem only when the trouble is
corrected.
3. The modem cannot be connected to pay telephones or party lines.
4. If requested by the telephone company, you must notify them of the following before the
MT3334HD8 is installed:
a. The particular phone line (phone number) to which the connection is to be made.
b. The FCC Registration Number:
AU7USA-24457-DE-N
c. The manufacturer’s name and model number:
Multi-Tech Systems - Model CC9600 CommPlete Communications Server
5. If the telephone company notifies you that your device is causing harm, unplug it. The telephone
company may disconnect your service if necessary and also may change its facilities, equipment,
operations or procedures which may affect operation of your equipment. Where practical, the
telephone company must promptly inform you in writing of the temporary disconnect or change in
service, give you the opportunity to make changes allowing uninterrupted service, and inform you of
your rights to bring a complaint to the FCC.

iv CommPlete Communications Server
FCC Fax Warning
The Telephone Consumer Protection Act of 1991 makes it unlawful for any person to use a computer or
other electronic device to send any message via a telephone fax machine unless such message clearly
contains in a margin at the top or bottom of each page or the first page of the transmission, the date and
time it is sent and an identification of the business or other entity, or other individual sending the message
and the telephone number of the sending machine or such business, other entity, or individual.
See your fax software manual for setup details.
Canadian Limitations Notice
Notice: The ringer equivalence number (REN) assigned to each terminal device provides an indication of
the maximum number of terminals allowed to be connected to a telephone interface. The termination of
an interface may consist of any combination of devices subject only to the requirement that the sum of the
ringer equivalence numbers of all the devices does not exceed 5.
Notice: The Industry Canada label identifies certificated equipment. This certification means that the
equipment meets certain telecommunications network protective, operational and safety requirements.
Industry Canada does not guarantee the equipment will operate to the user’s satisfaction.
Before installing this equipment, users should ensure that it is permissible to be connected to the facilities
of the local telecommunications company. The equipment must also be installed using an acceptable
method of connection. The customer should be aware that compliance with the above conditions may not
prevent degradation of service in some situations.
Repairs to certified equipment should be made by an authorized Canadian maintenance facility designated
by the supplier. Any repairs or alterations made by the user to this equipment, or equipment
malfunctions, may give the telecommunications company cause to request the user to disconnect the
equipment.
Users should ensure for their own protection that the electrical ground connections of the power utility,
telephone lines and internal metallic water pipe system, if present, are connected together. This precaution
may be particularly important in rural areas.
Caution: Users should not attempt to make such connections themselves, but should contact the
appropriate electric inspection authority, or electrician, as appropriate.

CommPlete Communications Server
v
Table of Contents
1 Introduction
Introduction ...................................................................................................................................................... 2
LED Indicators................................................................................................................................................... 2
Power Supply..................................................................................................................................................... 2
Manual Organization......................................................................................................................................... 3
Technical Specifications.................................................................................................................................... 6
2 Installation
Introduction ...................................................................................................................................................... 8
Safety Warnings................................................................................................................................................. 8
Pre-Installation Notes ....................................................................................................................................... 9
Installation Procedure....................................................................................................................................... 9
3 AT Commands
Working with AT Commands ..........................................................................................................................12
Modes of Operation .....................................................................................................................................12
Command Structure ....................................................................................................................................12
Command Editing........................................................................................................................................13
Dialing Commands...........................................................................................................................................16
Dial Modifier Commands.................................................................................................................................16
Phone Number Memory Commands...............................................................................................................19
Configuration Storage and Recall Commands.................................................................................................20
Modem Response (Result Code) Commands..................................................................................................21
Online Connection Commands........................................................................................................................24
V.34 Commands ...............................................................................................................................................28
RS-232 Interface Commands ...........................................................................................................................29
Error Correction and Data Compression Commands.....................................................................................31
Speed Conversion Commands .........................................................................................................................33
Immediate Action Commands.........................................................................................................................35
Flow Control Commands .................................................................................................................................36
Escape Sequences .............................................................................................................................................39
Remote Configuration Commands..................................................................................................................40
Line Probe Commands.....................................................................................................................................41
Diagnostic Commands .....................................................................................................................................42
4 S-Registers
Introduction .....................................................................................................................................................46
S-Registers ........................................................................................................................................................46
Reading and Assigning S-Register Values .......................................................................................................51
Examples of Assigning Values.....................................................................................................................51
Examples of Reading Values .......................................................................................................................51
AT Commands that Affect S-Registers ............................................................................................................51

vi CommPlete Communications Server
5 Testing the MT3334HD8
Introduction .....................................................................................................................................................54
Local Analog Loopback Test (V.54 Loop 3) ....................................................................................................54
Remote Digital Loopback Test (V.54 Loop 2) .................................................................................................55
Local Digital Loopback Test (V.54 Loop 2) .....................................................................................................57
6 Warranty, Service, and Technical Support
Limited Warranty.............................................................................................................................................60
Service...............................................................................................................................................................61
Technical Support ............................................................................................................................................61
Recording Product Information .................................................................................................................61
The Multi-Tech BBS.........................................................................................................................................62
Logging onto the Multi-Tech BBS...............................................................................................................62
Downloading a File......................................................................................................................................62
Reading a Message.......................................................................................................................................63
Leaving a Message .......................................................................................................................................63
Bulletins.......................................................................................................................................................63
About CompuServe ..........................................................................................................................................63
About the Internet............................................................................................................................................64
About the Multi-Tech Fax-Back Service..........................................................................................................64
Upgrading the MT3334HD8 Firmware............................................................................................................65
Using FlashPro to Upgrade Firmware ........................................................................................................65
Appendix A ASCII Conversion Chart.......................................................68
Appendix B Dial Pulses and Tones...........................................................69
Appendix C Result Code Summary...........................................................71
Appendix D S-Register Summary................................................................73
Appendix E AT Command Summary.......................................................75
Appendix F Remote Configuration.............................................................85
Index .........................................................................................................................................................87

CommPlete Communications Server 1
1 Introduction

MT3334HD8 User Guide
2CommPlete Communications Server
Introduction
The Multi-Tech MT3334HD8 is a high speed, high density modem card for the CommPlete
Communications Server. Each MT3334HD8 card contains eight integrated 33,600 bps modems. Each
modem on the MT3334HD8 card can be configured independently of the others via the CommPlete
Communications Server’s MR9600 controller, which can support and control up to 12 cards per rack.
Users dial into the MT3334HD8’s modems through a T1 daughter card on the RASCard that controls the
segment. There are no external connectors on the MT3334HD8.
Up to three MT3334HD8 cards can be installed per T1 segment. With eight modems per card, the
CommPlete Communications Server can support up to 24 simultaneous data lines per segment, or 96 per
CommPlete Communications Server
The MT3334HD8 operates as an enhanced ITU-T V.34 dial-up modem with a maximum speed of 33,600
bits per second (bps). As such, it includes the advanced features of Multi-Tech standalone modems such as
the popular MultiModemZDXb.
The MT3334HD8 is registered by the FCC for direct connection to the public telephone networks. No Data
Access Arrangements (DAAs) are required.
The MT3334HD8 is fully compatible with the standard AT command set, and is therefore compatible with
all popular communications software packages.
This user guide will help you to install, configure, test, and use the MT3334HD8.
LED Indicators
The MT3334HD8 has 16 LED indicators on the front panel, two for each modem:
CD Carrier Detect. The CD LED lights when the modem detects a valid carrier signal.
OH Off Hook/Out of Service. The OH LED lights when the modem is off hook, which occurs when the
modem is dialing, online, or answering a call. The LED flashes when the modem is in the busy-out
or out-of-service state.
Power Supplies
DC voltages are supplied to all modems in the CC9600 rack through two PS9600 universal input switching
power supplies designed for conventional 115 or 230 VAC input. The power supplies are designed for
redundant, fail-safe operation. If one should fail, the other can supply the power requirements of the entire
CommPlete Communications Server. Each PS9600 power supply has one LED indicator that indicates the
presence of all supply voltages.
Manual Organization
Chapter 1 Introduction
This chapter describes the MT3334HD8 and its LED indicators, gives its technical specifications, and
provides a guide to the organization of the manual.

1 Introduction
CommPlete Communications Server 3
Chapter 2 Installation
This chapter describes how to install the MT3334HD8 into the CC9600 chassis.
Chapter 3 Command Mode Operation
This chapter provides an introduction to MT3334HD8 command mode fundamentals, followed by a
detailed explanation of each AT command, providing examples where applicable.
Chapter 4 S-Registers
This chapter describes the MT3334HD8’s S-registers, which are used to store various modem options.
Each S-register is defined and explained.
Chapter 5 Testing the MT3334HD8
This chapter describes loopback testing for the MT3334HD8.
Chapter 6 Warranty, Service, and Technical Support
This chapter provides the terms of the MT3334HD8’s warranty, instructions for obtaining factory service,
and information about Multi-Tech’s BBS and technical support. Information on upgrading the
MT3334HD8’s firmware is also provided.
Appendix A ASCII Conversion Chart
Appendix B Dial Pulses and Tones
Appendix C Result Code Summary
Appendix D S-Register Summary
Appendix E AT Command Summary
Appendix F Remote Configuration

MT3334HD8 User Guide
4CommPlete Communications Server
Technical Specifications
Model Number MT3334HD8
Data Rates (Modem) Eight independent modems (Modem A, B, C, D, E, F, G, H), each operating at
33,600, 31,200, 28,800, 26,400, 24,000, 21,600, 19,200, 16,800, 14,400, 12,000,
9600, 4800, 2400, 1200, or 0-300 bps
Data Rates (Fax) 14,400, 9600, 4800, and 2400 bps
Data Format
(Modem)
Serial, binary, asynchronous at all data rates
Configuration Each of the card’s modems is independently configurable
Compatibility (Modem) ITU-T V.42bis, V.42, V.34plus, V.34, ITU-T V.32bis, V.32, V.25bis, V.21,
V.22bis, V.22, V.23, V.17, Bell 212A* and 103/113*
Compatibility (Fax) ITU-T Group 3, T.4, T.30, V.21, V.27ter, V.29, V.17, and EIA TR29.2
Error Correction ITU-T V.42 (MNP® Classes 3 and 4, and LAP-M)
Data Compression ITU-T V.42bis (4:1 throughput) or MNP 5 (2:1 throughput)
Speed Conversion Serial port data rates ad
j
ustable to 300, 1200, 2400, 4800,9600, 19,200, 38,400,
57,600, and 115,200 bps
Flow Control XON/XOFF, CTS/RTS, ENQ/ACK
Mode of Operation Half or full duplex over dial-up lines; automatic or manual dialin
g
, automatic
or manual answer
Intelligent Features Fully AT command compatible; auto dial; redial; repeat dial*; dial linking*;
pulse or tone dial; dial pauses; call status display; auto-parity and data rate
selection; keyboard-controlled modem options; nonvolatile memory; on-
screen displays of modem parameters, stored telephone numbers, and help
menus; and remote configuration.
AT Commands 100% compatible with standard AT command set
Command Buffer 60 characters
Automatic Dialing Standard AT command asynchronous dialing
Modem Modulations FSK at 300 bps, PSK at 1200 bps, QAM at 2400, 4800, and 9600 bps (non-
trellis), QAM with trellis-coded modulation (TCM) at 9600, 12,000, 14,400,
16,800, 19,200, 21,600, 24,000, 26,400, 28,800, 31,200, and 33,600 bps
Fax Modulations V.21 CH2 FSK at 300 bps
V.27ter DPSK at 4800 and 2400 bps
V.29 QAM at 9600 and 7200 bps
V.17TCM at 14400, 12000, 9600, and 7200 bps
Carrier Frequencies
ITU-T V.34
1600, 1646, 1680, 1800, 1829, 1867, 1920, 1959, 2000 Hz
Carrier Frequencies:
V.22bis/V.22 or
Bell 212A Standard
Transmit originate:
Transmit answer:
Receive originate:
1200 Hz
2400 Hz
2400 Hz

1 Introduction
CommPlete Communications Server 5
(2400 & 1200 bps) Receive answer: 1200 Hz
Carrier Frequencies:
Bell 103/113
(300 bps)
Transmit originate:
Receive originate:
Transmit answer:
Receive answer:
1270 Hz mark
1070 Hz space
2225 Hz mark
2025 Hz space
2225 Hz mark
2025 Hz space
1270 Hz mark
1070 Hz space
Carrier Frequencies:
V.21
Transmit originate:
Receive originate:
Transmit answer:
Receive answer:
980 Hz mark
1180 Hz space
1650 Hz mark
1850 Hz space
1650 Hz mark
1850 Hz space
980 Hz mark
1180 Hz space
Carrier Frequencies:
V.23
Transmit originate:
Receive originate:
Transmit answer:
Receive answer:
390 Hz mark
450 Hz space
1300 Hz mark
2100 Hz space
1300 Hz mark
2100 Hz space
390 Hz mark
450 Hz space
Fax Modulations 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
Fax Carrier
Frequencies
V.21 CH2 (half duplex)
1650 Hz mark, 1850 Hz space for transmit originate
1650 Hz mark, 1850 Hz space for transmit answer
V.27ter: 1800 Hz Originate/Answer
V.29 QAM: 1700 Hz Originate/Answer
V.17 TCM: 1800 Hz Originate/Answer
Transmit Level -13 dBm
Frequency Stability +0.01%
Receiver Sensitivity -43 dBm under worst case conditions
AGC Dynamic Range 43 dB
Serial Interface EIA RS-232C
Diagnostics Power-on self-test; ITU-T V.54 local analog loop, local digital loop, remote
digital loop.
Firmware Upgrades Flash memory; available on Multi-Tech’s BBS
Indicators LEDs for Carrier Detect and Off Hook/Out-Of-Service
Environmental Temperature range: 0°–50° C (32°–120° F)
Humidity range: 20–90% (noncondensing)

MT3334HD8 User Guide
6CommPlete Communications Server
Power
Requirements
5 VDC at 0.95 A
±16 VDC at 0.1 A
Power Consumption Approximately 6 watts
Dimensions 23.3 ×2.3 ×29.2 cm (9.2 ×0.9 ×11.5 in.) H ×W ×D
Weight 1.1Kg (2.5 lb.)
Limited Warranty Two years
Fuses F1 (+5 V), F2 (-16 V), F3 (+16 V)

CommPlete Communications Server 7
2 Installation

MT3334HD8 User Guide
8CommPlete Communications Server
Introduction
This chapter describes how to install the MT3334HD8 modem card into a CommPlete Communication
Server CC9600 chassis. This equipment should be installed only by a qualified service person.
The MT3334HD8 assembly consists of a high-density modem card and a front panel. Figure 1 shows the
layout of the MT3334HD8 card. The MT3334HD8 assembly plugs into power and data, Ethernet, and T1
bus connectors on the inside of the CC9600 chassis. There are no external connectors.
Connectors
LEDs
Figure 1. MT3334HD8 modem card.
Safety Warnings
✔Never install telephone wiring during a lightning storm.
✔Never install telephone jacks in wet locations unless the jacks are 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 electrical shock from lightning.
✔Do not use the telephone to report a gas leak in the vicinity of the leak
✔Ports that are connected to other apparatus are defined as SELV. To ensure conformity to EN 41003,
ensure that these ports are only connected to the same type on the other apparatus.

2 Installation
CommPlete Communications Server 9
Pre-Installation Notes
Warning: Interconnection directly, or by way of other apparatus, of ports marked “SAFETY WARNING
see instructions for use”with ports marked or not so marked may produce hazardous conditions on the
network. Advice should be obtained from a competent engineer before such a connection is made.
•All installation must be done by a qualified service person.
•To reduce emissions, be sure to use blanking plates to cover empty slots in the CC9600 chassis.
•Any other apparatus, including cable and wiring, connected between the MT3334HD8K modem and
the point of connection to any speech band circuit shall comply with the following:
1. The overall characteristics of this apparatus shall be such as to introduce no material effect upon
the electrical conditions presented to one another by the modem and he speech band circuit.
2. The apparatus shall comprise only
a. apparatus approved for the purpose of connection between the modem and a speech band
circuit; and
b. cable and wiring complying with a code of practice for the installation of equipment
covered by this part of BS 6328 or such other requirements as may be applicable.
Note: Such apparatus may have been approved subject to limitations in its use.
Installation Procedure
1. Unpack the MT3334HD8 assembly from its packaging and save the packaging for possible future
use. Perform a visual inspection of the MT3334HD8. If you are concerned about its condition, call
Technical Support for instructions.
2. Turn off both PS9600 power supplies.
3. The MT3334HD8 must be installed in a segment in which a RASCard with a T1 module is installed.
Remove a blank device panel or previous MT3334HD8 card from that segment.
4. Supporting the MT3334HD8 by the front panel and the bottom edge of the card, place it into the
CC9600’s open device slot. Make sure the edges of the MT3334HD8 card mate properly with the
guides of the device slot.
5. Slide the MT3334HD8 into the CC9600 chassis until you feel the MT3334HD8’s connectors mate with
the CC9600’s bus connectors.
6. Tighten the MT3334HD8’s retaining screws.
7. Turn on the PS9600 power supplies.
8. Note the PS9600 LED indicators. If they are not lit, see Chapter 5. If they are lit, proceed with
MultiModemManager operation (Chapter 4 of the MultiModemManager
Owner’s Manual ).
Note: A self-test runs each time the CommPlete Communications Server is turned on. Refer to Chapter 5
of the MultiModemManager Owner’s manual for more details on the power-on self-test.

CommPlete Communications Server 11
3 AT Commands

MT3334HD8 User Guide
12 CommPlete Communications Server
Working with AT Commands
The MT3334HD8’s modems are controlled by instructions called AT commands , so called because the
attention characters
AT precede each command or command string (sequence of commands). You can
send commands to the modem from your keyboard while in terminal mode, or you can use communi-
cations software to issue these commands automatically.
A MT3334HD8 modem is in command mode when it is not dialing or online. When it is in command
mode, you have access to a complete communications system that allows you to use several features,
including the basic AT command set described in this chapter. Using the basic AT command set, you can
enter phone numbers for automatic dialing, configure modem options, and monitor telephone activity. In
addition, you can command your modem to perform advanced features such as error correction, data
compression, speed conversion, and more.
This chapter describes the MT3334HD8’s operational modes, and shows you how to use each of the
MT3334HD8’s AT commands. MT3334HD8 commands and responses are compatible with all systems and
with all data communications software using the AT command set.
For easy reference, the MT3334HD8 has a help command that provides you with short, on-screen
descriptions of the modem commands. The help command is explained later in this chapter.
Modes of Operation
The MT3334HD8 operates in two basic functional modes: command mode and online mode . (There is also
an in-between state,
wait-for-carrier , in which the modem is out of command mode but not yet online.)
When you power up the modem, it is in command mode, and is ready to accept and respond to commands
from your keyboard or software.
An MT3334HD8 modem enters online mode after it dials, connects with another modem, and detects a
valid carrier signal. If it does not detect a carrier signal within the time frame controlled by register S7, the
modem abandons the call and re-enters command mode.
You can make the modem enter online mode without dialing by typing either the D command or the A
command.
The modem exits online mode if the carrier signal is lost or intentionally dropped. When this happens, the
modem hangs up and re-enters command mode.
By sending certain “escape”characters to the modem while online, you can make it enter command mode
without losing the carrier signal.
For auto answer-only applications, you can disable a modem’s ability to recognize AT commands by using
the %DC1 command. When you do this, the MT3334HD8 ignores all commands, and functions as a non-
intelligent modem. The %DC1 command and other MT3334HD8 commands are explained later in this
chapter.
Command Structure
You can control a wide variety of modem operations and options when the modem is in command mode.
AT commands tell the modem to dial a number, to answer a call, to operate at a certain speed, to use a
certain compression technique, and many other functions. AT commands consist of one or two letters,
which may be preceded by an ampersand (
& ), a dollar character ( $ ), a pound character ( # ), a percent
character (
% ), or a greater-than character ( > ). The Q command, for example, determines whether the
modem returns result codes, while the &QcommandselectswhichATcommandset themodem uses.

3 AT Commands
CommPlete Communications Server 13
A parameter after a command (0, 1, 2, etc.) tells the modem which option to use. If you do not specify a
parameter, the modem assumes the 0 (zero) option. E, for example, is the same as E0. You can issue
several commands on a single line (a command string) as long as the line does not exceed 60 characters.
Note that though Q1 is one command, it counts as two characters in the command line.
Each command has a valid range of parameters; for instance, &W can have only 0 or 1 as a parameter.
Valid commands generate an OK result code. A few generate an additional response, such as a list of
parameters. An invalid command, such as &W3, which has a parameter outside the valid range, generates
an ERROR
result code. Most commands have a default parameter, one that is enabled when the modem is
turned on or reset with the ATZ or AT&F command. Factory defaults are stored in read-only memory
(ROM), and cannot be changed. User-defined defaults can be stored in nonvolatile random-access
memory (NVRAM), and can be changed or deleted at will.
Command Editing
Always begin a command with the letters AT . You may type the command in upper case or lower case, but
not both. The AT command is not executed until you press the ENTER key. Use the BACKSPACE key to erase
the previous command character; it will not erase the AT characters once they are typed. If your keyboard
has no BACKSPACE key, use CTRL+H. You can change the character recognized by the modem as BACKSPACE
to any other ASCII character by changing register S5.
To cancel an entire command that has been typed but not yet executed, press CTRL+X. This also clears the
command buffer. The effect is the same as backspacing the command, only quicker.
The MT3334HD8 stores characters entered in a command in the modem’s command buffer until they are
executed by pressing ENTER. The command buffer’s capacity is 60 characters. The attention characters
(AT) do not count in the 60 allowed command characters. You may use spaces for increased readability
when typing a command; they are neither stored in the command buffer nor counted in the 60 allowed
characters. Hyphens, parentheses, etc., are not allowed.
If you exceed the 60-character limit or type invalid characters, the command buffer is automatically erased
and an ERROR
message is displayed. You must then retype the command within the 60-character limit,
using only the allowed characters.
The commands in this chapter are organized by function. A brief summary follows.

MT3334HD8 User Guide
14 CommPlete Communications Server
Table 1. AT Commands by Function
Topic Command Description Page
Dialing Action D Dial 16
A: Continuous redial
HOn-hook/off-hook
Dial Modifiers P Pulse dialing 16
TTone dialing
WWait for new dial tone
RReverse originate/answer mode
,Dialing pause
:Continuous redial
;Return to command mode after dialing
!Flash on-hook
@Quiet answer
$Call card tone detect
Phone Number D...N Store a phone number 19
Memory N Dial a stored number
N...N Number linking
LList stored telephone numbers
Configuration &W Store configuration 20
Storage & Recall &F Load default configuration
ZReset modem
Modem Responses E Echo command mode characters 21
(Result Codes) Q Result codes: enable/disable
&Q Result codes: Multi-Tech or standard
VResult codes: verbose/terse
XResult codes and call progress
&A Answerback
Online Connection #A Auto speed detection 24
BAnswer tone
%DC Command mode control
&CD Cleardown at disconnect
>DT DTMF detection
#F Fallback modes when online
&G Guard tones
*H Busy-Out After Disconnect
&P Pulse dial ratios
&RD Square wave ring detect
$T Calling tones
#T Trellis-coded modulation
YLong space disconnect
V.34 Controls %F Echo canceler frequency offset comp. 28
&RA Asymmetric bit rate
RS-232 Interface &C Carrier Detect control 29
Controls &D Data Terminal Ready control
&R Clear to Send control
&S Data Set Ready control
&RF CTS/RTS interaction control
&SF DSR/CD interaction control