Multitech MT9234SMI-HV-92, MT9234SMI-P-92, MT9234SMI-L-92, MT9234SMI-92, MT9234SMI-P-HV-92 Command Reference Manual

MultiModem® & SocketModem®

MT9234 Series

AT Commands

Reference Guide

Copyright and Technical Support

AT Commands Reference Guide for the MultiModem and SocketModem MT9234 Series

MT9234SMI
MT9234ZBA
MT9234ZBA-USB
MT9234MU
MT9234ZPX-UPCI
MT9234ZPX-PCIE
ISI9234PCIE

PN S000434D, Version D

Copyright

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 © 2007-2008, by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representations or warranty with respect to the contents hereof and
specifically disclaim 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.

Revisions
Revision Level Date Description

A 04/13/07 Initial release.
B 07/12/07 Updated the Escape Sequence text. Added a statement indicating that

some commands may not apply to every MT9234 build option. Deleted
the $LL command. Updated the $LB command.

08/09/07 Added a note that Voice commands other individual commands cannot

be used with the SMI build.
C 10/17/07 Added ISI9234PCIE to the product list to which these commands apply.
Updated the Technical Support list.
D 03/25/08 Removed +VDT comman d. Removed S2 range of 128-255. Changed

S24 default to 0. Changed S89 default to 0 and range to 0, 5-65.

Changed Communciation Standard Setting command "B" default to 0,15.
Added values 4 and 6 to &T command.

Trademarks

Multi-Tech registered trademarks include the Multi-Tech logo, MultiModem, and SocketModem.

World Headquarters

Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, MN 55112
Phone: [phone] or 800-328-9717
Fax: [phone]
Internet Address: http://www.multitech.com

Technical Support
Country By Email By Phone

Europe, Middle East, Africa [e-mail] +(44) 118 959 7774
U.S., Canada, all others [e-mail] [phone] or +[phone]

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 2

Table of Contents

Contents

Chapter 1 – AT Commands, S-Registers, and Result Codes .................................................................6

Introduction................................................................................................................................................6

A Note About Fax Commands...................................................................................................................6

Data and General Commands...................................................................................................................7

AT Attention Code...........................................................................................................................7

ENTER Key...........................................................................................................................................7

+++AT Escape Sequence...............................................................................................................7

A/ Repeat Last Command.................................................................................................................7

A Answer..........................................................................................................................................7

B Communication Standard Setting.................................................................................................7

D Dial................................................................................................................................................8

E Echo Command............................................................................................................................9

F Online Data Character Echo Command .......................................................................................9

H Hook Control.................................................................................................................................9

I Request ID Information...............................................................................................................10

M Monitor Speaker Mode ...............................................................................................................10

N Modulation Handshake...............................................................................................................11

O Return Online to Data Mode.......................................................................................................11

P Set Pulse or Tone Dialing Default...............................................................................................11

Q Result Codes Enable/Disable.....................................................................................................11

Sr= S-Register Control...................................................................................................................12

T Select Tone Dialing.....................................................................................................................12

V Result Code Format....................................................................................................................12

W Result Code Options...................................................................................................................12

X Select Result Code and Monitor Call Progress..........................................................................13

Z Reset and Recall Stored Profile..................................................................................................13

&C Data Carrier Detect (DCD) Control..........................................................................................14

&D Data Terminal Ready (DTR) Control.......................................................................................14

&E XON/XOFF Pacing Control......................................................................................................14

&F Restore Factory Default Configuration....................................................................................14

&G V.22bis Guard Tone Control....................................................................................................15

&K Local Flow Control Selection...................................................................................................15

&L Leased Line Operation ............................................................................................................15

&P Pulse Dial Make-to-Break Ratio Selection ..............................................................................15

&Q Asynchronous Communications Mode....................................................................................16

&S Data Set Ready (DSR) ............................................................................................................16

&T Self-Test Commands...............................................................................................................16

&V View Active Configuration........................................................................................................16

&W Store Current Configuration.....................................................................................................17

&Z Store Dialing Location and Number ........................................................................................17

\A Select Maximum MNP Block Size ..............................................................................................17

\B Transmit Break............................................................................................................................17

\K Break Control..............................................................................................................................18

\N Error Correction Mode Sel ection................................................................................................18

\Q Local Flow Control Selection......................................................................................................19

\T Inactivity Timer............................................................................................................................19

\V Protocol Result Code..................................................................................................................19

\X XON/XOFF Pass-Through..........................................................................................................19

-C Data Calling Tone ......................................................................................................................19

%A Adaptive Answer Result Code Enable ....................................................................................20

%B View Numbers in Blacklist .......................................................................................................20

%C Data Compression Control......................................................................................................20

%DC AT Command Control...........................................................................................................20

%DT Set AT Command Mode Timer............................................................................................21

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%E Fallback and Fall Forward Control...........................................................................................21

%H Set Callback Security – Direct Connect Enable......................................................................21

%S Command Speed Response ...................................................................................................21

+A8E V.8 and V.8bis Operation Controls......................................................................................22

+A8T Send V.8 bis Signal and/or Message...................................................................................23

+DCS Select V.42bis or V.44 Data Compression...........................................................................23

+DR V.44 Data Compression Reporting..........................................................................................24

+DS V.42bis Data Compression......................................................................................................24

+DS44 V.44 Data Compression....................................................................................................25

+EB Break Handling in Error Control Operation..............................................................................26

+EFCS 32-bit Frame Check Sequence.........................................................................................26

+ER Error Control Report ................................................................................................................26

+ES Error Control Selection............................................................................................................27

+ESA Set Up Error Control Parameters.........................................................................................27

+ETBM Call Termination Buffer Management...............................................................................27

+FCLASS Fax Class Indication .......................................................................................................28

+GCAP Complete List of Capabilities Request..............................................................................28

+GCI Country of Installation...........................................................................................................28

+GMI Manufacturer Identification Request ....................................................................................28

+GMM Model Identification Request.............................................................................................28

+GMR Revision Request.................................................................................................................28

+IFC DTE-DCE Local Flow Control ..............................................................................................29

+ILRR DTE-DCE Local Rate Reporting..........................................................................................29

+IPR= Fixed DTE Rate....................................................................................................................29

+ITF= Transmit Flow Control Threshold.........................................................................................30

+MR Modulation Reporting Control ..............................................................................................30

+MS Modulation Selection............................................................................................................30

$D DTR Dialing.............................................................................................................................32

$EB Asynchronous Word Length ....................................................................................................32

$LB Long Break ..............................................................................................................................32

$MB Online BPS Speed ...............................................................................................................32

$RP Ring Priority vs. AT Command Priority....................................................................................33

$SB Serial Port Baud Rate..............................................................................................................33

+VDR Distinctive Ring Report.........................................................................................................33

#CBS Callback Enable/Disable......................................................................................................36

#P Set 11-bit Parity.......................................................................................................................34

#S Enter Setup Password.............................................................................................................34

#S= Store Setup Password.............................................................................................................34

%%%ATMTSMODEM<CR> Remote Configuration Escape Sequence.........................................34

+VCID= Caller ID Selection............................................................................................................34

Callback Security Commands..................................................................................................................35

#CBA Callback Attempts ................................................................................................................35

#CBD Callback Delay .....................................................................................................................35

#CBF? Callback Failed Attempts Display.....................................................................................35

#CBFR Callback Failed Attempts Reset........................................................................................35

#CBI Local Callback Inactivity Timer.............................................................................................35

#CBN Store Callback Password.....................................................................................................35

#CBP Callback Parity .....................................................................................................................36

#CBR Callback Security Reset.......................................................................................................36

S-Registers..............................................................................................................................................37

Result Codes ...........................................................................................................................................40

Chapter 4 – Voice Commands .................................................................................................................42

Introduction..............................................................................................................................................42

Voice S-Register Summary .....................................................................................................................43

Voice Commands.....................................................................................................................................43

Commands That Change for Voice Mode Support..................................................................................43

Voice +V Commands Detail.....................................................................................................................44

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+FCLASS= 8 Select Voice Mode....................................................................................................44

+VNH Automatic Hang-Up Control .................................................................................................44

+VIP Initialize Voice Parameters...................................................................................................44

+VRX Enter Voice Receive State ...................................................................................................44

+VTS Send Voice Tone(s)..............................................................................................................45

+VTX Start Voice Transmission Process .......................................................................................46

+VGR Voice Gain for Received Voice Samples .............................................................................46

+VGT Set the Volume for Transmitted Voice Samples ..................................................................46

+VIT Set DTE/DCE Inactivity Timer..............................................................................................47

+VLS Select Analog Source/Destination........................................................................................48

+VRA Ringback Goes Away Timer.................................................................................................49

+VRN Ringback Never Appeared Timer.........................................................................................49

+VSD Silence Detection Sensitivity ................................................................................................50

+VSM Select Voice Compression Method......................................................................................51

+VTD=<dur> Beep Tone Duration Timer (DTMF/Tone Generation Duration)................................52

+VDR Distinctive Ring (Ring Cadence Reporting)..........................................................................53

+VEM Event Reporting and Masking..............................................................................................54

Interface Configuration Commands.........................................................................................................55

+VBT Set Modem Flow Control Assert and Deassert Points.........................................................55

+VPP Enable or Disable Voice Mode Packet Protocol...................................................................56

+VPR Select DTE/DCE Interface Rate (Turn Off Autobaud)..........................................................56

Flow Control.............................................................................................................................................57

Voice Mode Result Codes .......................................................................................................................57

Unsolicited Voice Mode Result Codes.....................................................................................................58

Valid Complex Event Report Tags......................................................................................................58

Voice Mode Shielded Codes ...................................................................................................................59

DTE/DCE Interface Rates........................................................................................................................61

Index...........................................................................................................................................................62

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 5

Chapter 1 – AT Commands, S-Registers, and Result Codes

Chapter 1 – AT Commands, S-

Registers, and Result Codes

Introduction

The AT commands are used to control the operation of your modem. They are called AT commands
because the characters AT must precede each command to get the ATtention of the modem.

AT commands can be issued only when the modem is in command mode or online command mode.

• The modem is in command mode whenever it is not connected to another modem.

• The modem is in data mode whenever it is connected to another modem and ready to exchange

data. Online command mode is a temporary state in which you can issue commands to the
modem while connected to another modem.

• To put the modem into online command m ode from data m ode, you must issue an escape

sequence (+++AT) and the command, e.g., +++ATH to hang up the modem. To return to data
mode from online command mode, you must issue the command ATO.

To send AT commands to the modem you must use a communications program, such as the
HyperTerminal applet in Windows or some other available terminal program. You can issue commands to
the modem either directly, by typing them in the terminal window of the communications program, or
indirectly, by configuring the operating system or communications program to send the commands
automatically. Fortunately, communications programs make daily operation of modems effortless by
hiding the commands from the user. Most users, therefore, need to use AT commands only when
reconfiguring the modem; e.g., to turn auto answer on or off.

The format for entering an AT command is ATXn, where X is the command and n is the specific value for
the command, sometimes called the command parameter. The value is always a number. If the value is
zero, you can omit it from the command; thus, AT&W is equivalent to AT&W0. Most commands have a
default value, which is the value that is set at the factory. The default values are shown in the “AT
Command Summary”.

You must press ENTER (it could be some other key depending on the terminal program) to se nd the
command to the modem. Any time the modem receives a command, it sends a response known as a
result code. The most common result codes are OK, ERROR, and the CONNECT messages that the
modem sends to the computer when it is connecting to another modem. See a table of valid result codes
at the end of this chapter.

You can issue several commands in one line, in what is called a command string. The command string
begins with AT and ends when you press ENTER. Spaces to separate the commands are optional; the
command interpreter ignores them. The most familiar command string is the initialization string, which is
used to configure the modem when it is turned on or reset, or when your communications software calls
another modem.

Note: This document applies to all the MT9234 products. However, some command s may not apply to all

MT9234 builds.

A Note About Fax Commands

Fax commands are covered in two separate fax reference guides. These guides are included on the
product CD and are posted on the Multi-Tech Web site:

http://www.multitech.com/DOCUMENTS/Families/MultiModemZBA/manuals.asp

.

• Fax Service Class 1 and Fax Service Class 1.0 Developer's Guide.

Document number: S000262x

• Fax Developer's Guide for Classes 2 and 2.0/2.1

Document number: S000239x

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 6

Chapter 1 – AT Commands, S-Registers, and Result Codes

Data and General Commands

AT Attention Code

Description: The attention code precedes all command lines except A/, A: and escape sequence s.

ENTER Key

Description: Press the ENTER (RETURN) key to execute a command.

+++AT Escape Sequence

Syntax: +++AT<CR>
Description: Allows the modem to exit data mode and enter on-line command mode. While in on-

line command mode, AT commands are sent directly to the modem.

Use the return to on-line data mode command (O<value> – Return to On-Line Data

Mode) to return to data mode.

A/ Repeat Last Command

Syntax: A/
Description: This command repeats the last AT command. The modem repeats the command

currently in the command buffer.
IMPORTANT:
Do not use the AT prefix with this command.
Do not conclude the command with a terminating character (E

A Answer

Syntax: ATA
Description: This command instructs the modem to connect to the line and establish a connection

with the remote modem or DCE. This command can be canceled if the modem

receives a new command or character from the host system before the handshake

begins.
Result Codes: CONNECT if a connection is established and the extended result code parameter is

equal to 0. (See X<value> – Select Result Code and Monitor Call Progress).

CONNECT <rate> if a connection is established and the extended result code

parameter is not equal to 0.

NO CARRIER if a connection cannot be established or the modem aborts the

connection on request of the host system.

OK if the commands are aborted or DTR is turned off by the host system when the

data terminal ready control is not set to 0. See &D – DTR Control.

ERROR if the modem is in on-line command mode when receiving the A command.

B Communication Standard Setting

Description: This comma nd selects the communication standard used by the modem.
Syntax: ATB<value>
Values: 0 Selects CCITT V.22 mode when modem is at 1200 bps.
1 Select Bell 212A when modem is at 1200 bps.
2 Deselect V.23 reverse channel (same as B3).
3 Deselect V.23 reverse channel (same as B2).
15 Select V.21 when the modem is at 300 bps.
16 Select Bell 103J when the modem is at 300 bps.
Defaults: 0 and 15
Result Codes: OK if <value> = 0-3, 15, 16
ERROR if <value> ≠ 1.

NTER).

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 7

Chapter 1 – AT Commands, S-Registers, and Result Codes

D Dial

Description: This comma nd instructs the modem to begin the dialing sequence. The dial string,

which is made up of the telephone number and dial modifiers is entered after the D

command.
A dial string can be up to 60 characters long. Any digit or symbol may be dialed as

touchtone digits. Characters such as spaces, hyphens, and parentheses are ignored

by the modem and may be included in the dial string to enhance readability.
Syntax: ATD<dial_strings>
Dial String Values: Phone number and dial modifiers.

Dial string modifiers:

L Redial the last number. (Must be placed immediately after ATD.)
P Select pulse-dialing.
T Select tone-dialing.
V Dial using speakerphone. Instructs the modem to switch to speakerphone

mode and dial the number. Use the ATH command to disconnect the voice
call.

W Wait for dial tone. This command instructs the modem to wait for a second

dial tone before processing the dial string. (X2, X4, X5, X6, or X7 must be
selected.)

, Pause during dialing for the amount of time set in register S8.
; Return to command mo de. Instructs the modem to return to command mode

after it has finished dialing without disconnecting the call. This modifier must
be the last character in the dial string.

! Hook flash. Instructs the modem to go on-hook for 0.5 seconds and then

return to off-hook.

@ Wait for quiet answer. Instructs the modem to wait for 5 seconds of silence

after dialing the number. If silence is not detected, the modem sends a NO
ANSWER result code back to the user.

^ Disable data calling tone transmission.
$ Detect AT&T call card “bong” tone. The character should follow the phone

number and precede the user’s call card number:

ATDT1028806127853500$

S=<location> Dial a number previously stored in the register. Instructs the modem

to dial a telephone number previously stored using the
&Z<location>=<dial_string> command. Valid storage locations are 0 to 2

(0–1 for Parallel {internal}).
Example: ATDS=2
Default: T

Result Codes: CONNECT if a connection is established and the extended result code

parameter is equal to 0. (See X<value> – Select Result Code and
Monitor Call Progress).

CONNECT <rate> if a connection is established and the extended result code

parameter is not equal to 0.

NO CARRIER if a connection cannot be established or the modem aborts the

connection on request of the host system.

BUSY if the W or @ modifiers are used and a busy signal is detected.
NO ANSWER if the @ modifiers is used and the remote ring followed by 5

seconds of silence is not detected before expiration of the connection
timer. See S7 – Connection Completion Time-Out.

OK if the commands are aborted or DTR is turned off by the host system when

the data terminal ready control is not set to 0. See &D<value> – Data
Terminal Ready (DTR) Control.

ERROR if the modem is in on-line command mode when receiving the A

command.

123456789

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 8

Chapter 1 – AT Commands, S-Registers, and Result Codes

E Echo Com m and

Description: Enables or disables the modem's echo feature. When the echo feature is selected

and the modem is in the command mode, characters sent to the modem are sent

back to the host and displayed on the monitor.
Syntax: ATE<value>
Values: 0 Do not echo keyboard input to the terminal.
1 Do echo keyboard input to the terminal.
Default: 1

F Online Data Character Echo Command

Description: Controller-b ased products support this command to ensure backward compatibility

with communications software that issues the F1 command.
Syntax: ATF<value>
Values: 0 Enable online data character echo. (Not supported.)
1 Disable online data character echo (included for backward compatibility).
Default: 1
Result Codes: OK if <value> = 1
ERROR if <value> ≠ 1.

H Hook Control

Description: Instructs the modem to go on-hook to disconnect a call or go off-hook to make the

telephone line busy.
Syntax: ATH<value>
Values: 0 Go on-hook (hang up).
1 Go off-hook (make the phone line busy).
Default: 0
Result Codes: OK if <value> = 0 to 1
ERROR if <value> ≠ 0 to 1.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 9

Chapter 1 – AT Commands, S-Registers, and Result Codes

I Request ID Information

Description: Use this command to display product information about the modem. In each case the

information is transmitted to the host system followed by a final result code.
Syntax: ATI<value>
Values: 0, 3 Returns the modem identity string and driver version number.
1 Calculates a ROM checksum and displays it on the DTE (e.g., 12AB).
2 Performs a ROM check, calculates the checksum, and then verifies the

checksum by displaying OK or ERROR.
4 Returns firmware version for the data pump (e.g., 94).
5 Returns the code version, board ID, and country/region ID in hexadecimal.
9 Returns the country/regional code in English.
11 Displays connection information as described below.
Default: 0
Result Codes: The ATI11 results are listed on two screens. To get to the second screen, press any

key or ESC to Exit. The following is an example of the ATI11 results.

Description Status

Last Connection V.92

Initial Transmit Carrier Rate 28800

Initial Receive Carrier Rate 50666

Final Transmit Carrier Rate 28800

Final Receive Carrier Rate 50666

Protocol Negotiation Result LAPM

Data Compression Result V44

Estimated Noise Level 46

Receive Signal Power Level (-dBm) 18

Transmit Signal Power Level (-dBm) 12

Round Trip Delay (msec) 10

Description Status

Near Echo Level (-dBm) NA

Far Echo Level (-dBm) NA

Transmit Frame Count 0

Transmit Frame Error Count 0

Receive Frame Count 1

Receive Frame Error Count 0

Retrain by Local Modem 0

Retrain by Remote Modem 0

Rate Renegotiation by Local Modem 0

Rate Renegotiation by Remote Modem 0

Call Termination Cause 0

Robbed-Bit Signaling 10

Digital Loss (dB) 6

Remote Server ID NA

Last PCM S PTR EBB3

Connection Time (msec) 19646

The ATI11 command may be issued from on-line command mode or after the end of
a call. After a call, some of the values are no longer valid.

M Monitor Speaker Mode

Description: Turns the speaker on and off.
Syntax: ATM<value>
Values: 0 Speaker always off.
1 Speaker on until carrier signal detected.
2 Speaker always on when modem is off-hook.
3 Speaker on until carrier is detected, except while dialing.
Default: 1
Result Codes: OK if <value> = 0 to 3
ERROR if <value> ≠ 0 to 3.

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Chapter 1 – AT Commands, S-Registers, and Result Codes

N Modulation Handshake

Description: Sets the modem protocol for handling handshake negotiation at connection time if

the communication speed of the remote modem is different from the speed of the
ATN<value>

Values: 0 Modem performs handshake only at communication standard specified by S-

Register S37 and the B<value> command.

1 Modem begins handshake at communication standard specified by S-Register

S37 and the B command. During handshake, fallback to a lower speed can

occur.
Default: 1
Result Codes: OK if <value> = 0 to 1
ERROR if <value> ≠ 0 to 1.

O Return Online to Data Mode

Description: Exits online command mode and enters online data mode. If the modem is not in

online command mode when this command is received, the modem generates an

ERROR result code.
Syntax: ATO<value>
Values: 0 Exits online command mode and returns to data mode.
1 Issues a retrain before returning to online data mode.
3 Issues a rate renegotiations before returning to online data mode.
Default: 0
Result Codes: CONNECT if <value> = 0, 1, 3 and result code an d call progress monitor are set to 0

(X0).

CONNECT <rate> if <value> = 0, 1, 3 and the result code and call prog ress monitor

are not set to 0 (X<value> where n = 1 to 7).

NO CARRIER if the connection is not successfully resumed.
ERROR if <value> ≠ 0, 1, 3.

P Set Pulse or Tone Dialing Default

Description: Configures the modem for pulse (non-touch-tone) or Tone dialing. All subseque nt

D<dial_string> commands use pulse dialing until either the T command or a tone

dial modifier is received by the modem. Tone dialing is the default setting. This

command does not use parameters and generates an ERROR re sult code when

parameters are attached to the command.
Syntax: ATP
Values: P Pulse Dialing
T Tone Dialing
Default: T

Q Result Codes Enable/Disable

Description: Result codes are informational messages sent from the modem and displayed on the

monitor. Basic result codes include OK, CONNECT, RING, NO CARRIER, and

ERROR.
Use the Q<value> command to enable or disable result code generation by the

modem. If result codes are disabled and an invalid parameter value is entered, the

modem does not generate an ERROR result code because result codes are turn off.
Syntax: ATQ<value>
Values: 0 Enable result codes.
1 Disable result codes.
Default: 0
Result Codes: OK if <value> = 0 to 1
ERROR if <value> ≠ 0 to 1.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 11

Chapter 1 – AT Commands, S-Registers, and Result Codes

Sr= S-Register Control

Description: Use this command to view or change an S-register. S-registers contain parameters

used by the modem. This command has two forms, one to show the contents of the

register and the other to change the contents of the register. Some registers are read

only and are not affected by the S<register number>=<value> command. Each

register has a specific function.
Syntax: ATS<register number>=<value> Sets the contents of the register to <value> if the

register is not read only.
ATS<register number>? Displays register contents.
Default: None
Result Codes: OK if <register number> is a valid register.

ERROR if <register number> is not a valid register.

T Select Tone Dialing

Description: Configures the modem for DTMF (touch-tone) dialing. All subsequent D<dial string>

commands use tone dialing until either the P command or a pulse dial modifier is

received by the modem. Tone dialing is the default setting. This command does not

use parameters and generates an ERROR result code when parameters are

attached to the command.
Syntax: ATT

V Result Code Format

Description: Controller-based modems generate result codes using one of two formats. Verbose

mode generates result codes in the familiar text formats using words. Numerical

mode generates result codes as a number. Each result codes has a number

assigned to it.
Use this command to switch between numerical and verbose modes.
Call progress and negotiation progress messages are affected by this command.
Syntax: ATV<value>
Values: 0 Displays result codes as digits (terse response).
1 Displays result codes as words (verbose response).
Default: 1
Result Codes: OK if <value> = 0 to 1.

ERROR if <value> ≠ 0 to 1.

W Result Code Options

Description: Use this command to select the modem's CONNECT message options.
Syntax: ATW<value>
Values: 0 CONNECT result code reports DTE receive speed; disables protocol result

codes.

1 CONNECT result code reports DTE receive speed; enables protocol result

codes.

2 CONNECT result code reports DCE receive speed; enables protocol result

codes.
Default: 2
Result Codes: OK if <value> = 0 to 2.
ERROR if <value> ≠ 0 to 2.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 12

Chapter 1 – AT Commands, S-Registers, and Result Codes

X Select Result Code and Monitor Call Progress

Description: Use this command to enable tone detection options used in the dialing process. As

each function is chosen, the modem’s result codes are also affected. Therefore, this
command is frequently used to control the modem’s responses. The primary function
of this command is to control call response capabilities.

Function Enabled Disabled

Ext Result Codes Modem displays basic result

codes, connect messages with
data rate, and an indication of
the modems error correction
and data compression
operations.

Dial Tone Detect Modem dials upon detection of

a dial tone, and disconnects the
call if the dial tone is not
detected within 10 seconds.

Busy Tone Detect Modem monitors for busy tones. Modem ignores any busy

Modem displays the basic
result codes.

Modem dials a call regardless
of whether it detects a dial
tone. Register S6 contains
the dial delay.

tones it receives.

Syntax: ATX<value>
Values: Command Extended Result Codes Dial Tone Detect Busy Tone Detect

0 Disabled Disabled Disabled

1 Enabled Disabled Disabled
2 Enabled Enabled Disabled
3 Enabled Disabled Enabled
4 Enabled Enabled Enabled
5, 6 Enabled Enabled Enabled
7 Disabled Enabled Enabled
Default: 4
Result Codes: OK if <value> = 0 to 7.
ERROR if <value> ≠ 0 to 7.
Call Progress Result Codes:
Command Result Codes

0 OK, RING, ERROR, CONNECT, NO CARRIER
1 OK, RING, ERROR, CONNECT<RATE>, NO CARRIER
2 OK, RING, ERROR, CONNECT<RATE>, NO CARRIER, NO DIALTONE
3 OK, RING, ERROR, CONNECT<RATE>, NO CARRIER, BUSY,

BLACKLISTED

4 OK, RING, ERROR, CONNECT<RATE>, NO CARRIER, BUSY,

BLACKLISTED, DELAYED, NO DIALTONE, CALL WAITING
DETECTED

5, 6 OK, RING, ERROR, CONNECT<RATE>, NO CARRIER, BUSY,

BLACKLISTED, DELAYED, NO DIALTONE, CALL WAITING
DETECTED

7 OK, RING, ERROR, CONNECT, NO CARRIER

Z Reset and Recall Stored Profile

Description: Use this command to make the modem go on-hook and restore the profile saved by

the last &W command.

Note: Both Z0 or Z1 restore the same profile (See &W – Store Current Configuration).

Agere Systems controller-based modems have only one stored profile.
Syntax: ATZ<value>
Values: 0 Reset and restore stored profile (saved by the last &W command).
1 Same as Z0.
Default: None
Result Codes: OK if <value> = 0 to 1.
ERROR if <value> ≠ 0 to 1.

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&C Data Carrier Detect (DCD) Control

Description: Use this command to control the modem’s response to receiving a remote modem's

carrier signal. Data carrier detect (DCD) is a signal from the modem to the computer

indicating that the carrier signal is being received from a remote modem. The modem

typically turns off DCD when it no longer detects the remote modem's carrier signal.
Syntax: AT&C<value>
Values: 0 DCD remains ON at all times.
1 DCD turns ON when the remote modem’s carrier signal is detected, and

turns OFF when the carrier signal is not detected.
Default: 1
Result Codes: OK if <value> = 0 to 1.

ERROR if <value> ≠ 0 to 1.

&D Data Terminal Ready (DTR) Control

Description: Use this command to select the modem’s response to the data terminal ready (DTR)

signal. The host system generates the DTR signal and supplies it to the modem.
Syntax: AT&D<value>
Values: 0 Modem ignores true status of DTR signal and treats it as always on. Use this

command if the computer does not provide DTR to the modem.

1 If DTR is not detected while in online data mode, the modem enters

command mode, issues an OK, and remains connected.

2 If DTR signal is not detected while in online data mode, the modem

disconnects.
3 Resets the modem on the on-to-off DTR transition.
Default: 2
Result Codes: OK if <value> = 0 to 3.

ERROR if <value> ≠ 0 to 3.

&E XON/XOFF Pacing Control

Description: Enables or disables XON/XOFF pacing.
Syntax: AT&E<value>
Values: 12 Disables XON/XOFF pacing.
13 Enables XON/XOFF pacing.
Default: 12
Result Codes: OK if <value> = 12 to 13.

ERROR if <value> ≠ 12 to 13.

&F Restore Factory Default Configuration

Description: Use this command to reset the modem to the configuration programmed at the

factory. This operation replaces all of the command options* and S-register settings
in the active configuration with factory default values.

Note: In voice mode, the command line is ignored if the AT&F command is placed on

the same line as the other commands. To load factory settings in voice mode, issue

the &F<value> command by itself.
Syntax: AT&F<value>
Values: 0 Loads factory settings as active configuration.
Default: None
Result Codes: OK if <value> = 0.
ERROR if <value> ≠ 0.

* There are several noted exceptions to this command and caution should be used

when determining the state of the command options once this command has been
executed.

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&G V.22bis Guard Tone Control

Description: Use this command to select which guard tone, if any, the modem will send while

transmitting in the high band (answer mode). This command is only used in V.22 and

V.22 bis mode. This option is not used in North America; it is for international use

only.
Syntax: AT&G<value>
Values: 0 Disables guard tone.
1 Sets guard tone to 550 Hz.
2 Sets guard tone to 1800 Hz.
Default: 0
Result Codes: OK if <value> = 0 to 2.

ERROR if <value> ≠ 0 to 2.
Note: The &G command is not used in North America.

&K Local Flow Control Selection

Description: Use this command to select a flow control method.
Syntax: AT&K<value>
Values: 0 Disables flow control.
3 Enables CTS/RTS hardware flow control.
4 Enables XON/XOFF software flow control.
Default: 3
Result Codes: OK if <value> = 0, 3, or 4.
ERROR if <value> ≠ 0, 3, or 4.

&L Leased Line Operation

Description: Sets standard dial-up or leased-line operation. Note: This command does not apply

to all models or build options.
Syntax: AT&L<value>
Values: 0 The modem is set for standard dial-up operation.
1 The modem is set for leased line operation in originate mode.
2 The modem is set for leased line operation in answer mode.
Default: 0

Note: For &L1 and &L2, there is a 30-second window betwe en power up and the

starting of the leased line handshake. During this time, you can turn off the

command, if desired.
Result Codes: OK if <value> = 0 to 2.

ERROR if <value> ≠ 0 to 2.

&P Pulse Dial Make-to-Break Ratio Selection

Description: Use this command to select the make-to-break ratio. This command is effective only

for Japan.
Syntax: AT&P<value>
Values: 0 Selects 39% to 61% make-to-break ratio at 10 pulses per second.
1 Selects 33% to 67% make-to-break ratio at 10 pulses per second.
2 Selects 33% to 67% make-to-break ratio at 20 pulses per second.
Default: 1
Note: The &P2 command is available only if the country/regional code is set to

Japan.
Result Codes: OK if <value> = 0 to 2.

ERROR if <value> ≠ 0 to 2.

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&Q Asynchronous Communications Mode

Description: This command is supported to ensure backward compatibility with communication

software that issues the &Q command. The preferred method for changing the

asynchronous communication mode is to use the \N command.
Syntax: AT&Q<value>
Values: 0 Asynchronous with data buffering. Same as \N0.
5 Error control with data buffering. Same as \N3.
6 Asynchronous with data buffering. Same as \N0.
8 MNP error control mode. If MNP error control is not established, the modem

falls back according to the setting in S36.

9 V.42 or MNP error control mode. If neither error control is established, the

modem falls back according to the setting in S36.
Default: 5
Result Codes: OK if <value> = 0, 5, 6, 8, or 9.

ERROR if <value> ≠ 0, 5, 6, 8, or 9.

&S Data Set Ready (DSR)

Description: Use this command to control DSR action.
Syntax: AT&S<value>
Values: 0 DSR is always ON.
1 DSR goes ON only during a connection.
Default: 0
Result Codes: OK if <value> = 0,1.

ERROR if <value> ≠ 0, 1.

&T Self-Test Commands

Description: Use this command to perform diagnostic tests on the modem. Each test is designed

to isolate a problem location when experiencing periodic data loss or random errors.
Syntax: AT&T<value>
Values: 0 Terminates the test in progress.
1 The &T1 command runs the Local Analog Loopback Test. This test verifies

modem's transmitter and receiver circuits are functioning properly. To work
properly, the modem must be off-line.

3 The AT3 runs the Local Digital Loopback Test. This test allows you to verify

that the remote computer or terminal, the remote modem, serial ports, the
telephone line, and the local modem are functioning properly. To work
properly, the modem must be online.

4 The &T4 command must be sent to the remote modem to run the Remote

Digital Loopback Test.

6 The &T6 command runs the Remote Digital Loopback Test. This test allows

you to verify that the local computer or terminal, the two modems, and the
transmission line between them are functioning properly. To work properly,

the modem must be online.
Default: None
Result Codes: OK if <value> = 0.
CONNECT if <value> = 0 or 3.

ERROR if <value> ≠ 0, 1, or 3.

&V View Active Configuration

Description: Use this command to view the active configuration.
Syntax: AT&V

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&W Store Current Configuration

Description: Use this command to store the modem's command options and all S- registers

except S3, S4, and S5. The Z0 command or a power-up reset of the modem restores

these profiles.
Note: This command is not valid during a cellular call.
Syntax: AT&W<value>
Values: 0 Stores current configuration as profile 0.
Default: 0
Result Codes: OK if <value> = 0.
ERROR if <value> ≠ 0.

&Z Store Dialing Location and Number

Description: Use this command to store a dialing string. Controller-based modems can save four

dialing stings. The format for the command is: &Z<storage_location> =

<dialing_string>. The dial string may contain up to 40 characters. The

ATDS=<storage_location> command dials using the stored string.

Syntax: AT&Z<location>=<stored number>
Values: <storage_location> = 0 to 2 for serial; 0 to 1 for parallel.
<dialing_string> = Dialing command.
Default: None
Result Codes: OK if <value> = 0 to 2.
ERROR if <value> ≠ 0 to 2.

\A Select Maximum MNP Block Size

Description: Use this command to select a MNP error corrected link with a maximum block size

controlled by the parameter <block size>.
Syntax: AT\A<value>
Values: 0 64-character maximum
1 128-character maximum
2 192-character maximum
3 256-character maximum
Default: 3
Result Codes: OK if <value> = 0 to 3.
ERROR if <value> ≠ 0 to 3.

\B Transmit Break

Description: Use this command in non-error-controlled mode. The command causes the modem

to transmit a break signal to the remote modem. The minimum break length is 100

ms and the maximum break length is 900 ms. The <break_time> parameter has

values between one and nine with each increment representing 100 ms. The default

of <value> = 3 corresponds to a length of 300 ms.
The command works in conjunction with the \K command.
Syntax: AT\B<value>
Values: <break_time> = 0–9 in 100 ms units
Default: 3 (300 ms)
Result Codes: OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1.

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\K Break Control

Description: Use this command to control the response of the modem to a break received from

the DTE, remote modem, or the \B<value> command. The command values are

different in three situations:
Syntax: AT\K<value>
Values: \K<value> – Modem Is Operating in Data Transfer Mode

The modem receives a break from the DTE when it is operating in data transfer

mode.

Values Function

0, 2, 4 Enter online command mode, no break sent to remote modem.
1 Clear data buffers and send a break to remote modem.
3 Send a break to the remote modem immediately.

5 Send a nondestructive, nonexpedited break to remote modem.

5 is the default.

\K<value> – Modem Is in Online Command Mode During Data Connection

The modem is in the online command state (waiting for AT commands) during a data

connection, and the \B<value> command is received in order to send a break to the

remote modem.

Values Function

0, 1 Clear data buffers and send break to the remote modem.
2, 3 Send a break to the remote modem immediately.
4, 5 Send a break to the remote modem in sequence with data.
4, 5 are the defaults.

\K<value> – Break Is Received During Connection
The modem receives a break from the remote modem during a connection.

Values Function

0, 1 Clear data buffers and send break to the DTE.

2, 3 Send a break to the DTE immediately.

4, 5 Send a break to the DTE in sequence with the received data.

4, 5 are the defaults.
Result Codes: OK if <value> = 0 to 5.

ERROR if <value> ≠ 0 to 5.

\N Error Correction Mode Selection

Description: Use this command to select the type of error control used by the modem when

sending or receiving data.
Syntax: AT\N<value>
Values: 0 Buffer mode. No error control (same as &Q6).
1 Direct mode.
2 MNP or disconnect mode. The modem attempts to connect using MNP2-4

error control procedures. If this fails, the modem disconnects. This is also
known as MNP reliable mode.

3 V.42, MNP, or buffered. The modem attempts to connect in V.42 error control

mode. If this fails, it will attempt to connect in MNP mode. If this fails, the
modem connects in buffer mode and continues operation. This is also known
as V.42/MNP auto reliable mode (same as &Q5).

4 V.42 or disconnect. The modem attempts to connect in V.42 error control

mode. If this fails, the modem disconnects.
5 V.42, MNP, or buffered (same as \N3).
7 V.42, MNP, or buffered (same as \N3).
Default: 3
Result Codes: OK if <value> = 0 to 5, or 7.
ERROR if <value> ≠ 0 to 5, or 7.

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Chapter 1 – AT Commands, S-Registers, and Result Codes

\Q Local Flow Control Selection

Description: Use this command to set the local flow control method.
Syntax: AT\Q<value>
Values: 0 Disable flow control (same as &K0).
1 XON/XOFF software flow control (same as &K4).
3 RTS/CTS to DTE. (same as &K3)
Default: 3
Result Codes: OK if <value> = 0, 1, 3.
ERROR if <value> ≠ 0, 1, 3.

\T Inactivity Timer

Description: Use this command to specify the delay time used by the inactivity timer. The delay

time is the length of time in minutes that the modem waits during periods of inactivity
before disconnecting. Periods of inactivity are defined by no data being sent or
received by the DCE. To disable the inactivity timer use the T0 command. The delay

time may also be specified in S-register S30.
Syntax: AT\T<value>
Values: 0 Inactivity timer disabled.
1 to 255 Specifies the length of time in minutes that the modem will wait before

disconnecting when no data is sent or received.
Default: 0
Result Codes: OK if <value> = 0 to 255.
ERROR if <value> ≠ 0 to 255.

\V Protocol Result Code

Description: Use this command to enable or disable protocol result codes.
Syntax: \V<value>
Values: \V0 Disables protocol result code appended to the DCE speed.
\V1 Enables protocol result code appended to the DCE speed.
\V2 Same as \V1.
Default: \V1
Result Codes: OK if <value> = 0, 1, 2.
ERROR if <value> ≠ 0, 1, 2.

\X XON/XOFF Pass-Through

Description: Use this command to restrict the XON/XOFF flow control to the local DCE for

processing or have the local DCE send the flow control characters to the remote

DCE.
Syntax: AT\X<value>
Values: 0 Modem processes XON/XOFF flow control characters locally.
1 Modem passes XON/XOFF flow control characters.
Default: 0
Result Codes: OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1.

-C Data Calling Tone

Description: Enables or disables the V.25 data calling tone to deny or allow data/fax/voice

discrimination. -
Syntax: AT-C<value>
Values: 0 Disable V.25 data calling tone to deny remote data/fax/voice discrimination.
1 Enable V.25 data calling tone to allow remote data/fax/voice discrimination.
Default: 1
Result Codes: OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1.

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Chapter 1 – AT Commands, S-Registers, and Result Codes

%A Adaptive Answer Result Code Enable

Description: The %A command controls whether the DATA or FAX result codes will be sent by the

modem. The modem must be in fax mode for this command to work. Also, the

modem must be set to +FAA=1, which enables the modem to distinguish between a

fax and a data call. When these commands are enabled, the modem sends DATA to

the computer when it detects data tones and FAX when it detects fax tones. These

strings are used by some servers to select the appropriate communication program..
Syntax: AT%A<value>
Values: 0 Disables adaptive answer result codes.
1 Enables adaptive answer result codes.
Default: 0
Result Codes: OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1

%B View Numbers in Blacklist

Description: Blacklisting is a method of handling failed or troubled calls encountered during

automatic dialing. This command is only used to display the contents of the blacklist

when blacklisting is active. It does not affect the functionality associated with

blacklisting.
When the blacklisting option is active, use this command to display the telephone

numbers and status of any failed or troubled calls. The blacklisting option is

associated with the country selection. Some countries have national requireme nts

which prohibit repeat calls to the same number through automatic dialing.
Syntax: AT%B
Values: N/A
Result Codes: <list of phone numbers and their status> if country supports blacklisting.

OK if no failed calls occur.
ERROR if country selection does not support blacklisting.

%C Data Compression Control

Description: Use this command to enable or disable data compression. This command enables or

disables V.44, V.42 bis, and MNP class 5 data compression. The command

overwrites the current status of the +DCS command. The command is also

overwritten by changes made by the +DCS command. On-line changes do not take

effect until a disconnect occurs.
Syntax: AT%C<value>
Values: 0 Disable V.42bis/MNP 5. No data compression.
1 Enable V.42bis/MNP 5. Data compression enabled.
Default: 1
Result Codes: OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1.

%DC AT Command Control

Description: Use this command to set whether or not the modem will respond to AT commands.

Note: This command does not apply to the parallel build.

Syntax: AT%DC<value>
Values: 0 The modem responds to AT commands. The modem will respond to

AT%DC for 10 seconds after it is turned on.
1 The modem ignores AT commands.
Default: 0

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Chapter 1 – AT Commands, S-Registers, and Result Codes

%DT Set AT Command Mode Timer

Description: Sets the length of time that the command mode will be disabled when set for %DC1

(the modem ignores AT commands).

Note: This command does not apply to the parallel build.

Syntax: AT%DT<value>
Values: 0-255 in 1 second increments
Default: 0

%E Fallback and Fall Forward Control

Description: This command provides the option for the modem to automatically monitor line

quality, to fall back when line quality is insufficient, and to fall forward when line

quality is sufficient.
Syntax: AT%E<value>
Values: 0 Disable fallback and fall forward.
1 Enable fallback and disable fall forward.
2 Enable fallback and fall forward.
Default: 2
Result Codes: OK if <value> = 0, 1, 2.
ERROR if <value> ≠ 0, 1, 2.

%H Set Callback Security – Direct Connect Enable

Description: Sets Callback Security to normal operation or to direct connect.
Note: This command does not apply to the parallel build.
Syntax: AT%H<value>
Values: 0 Sets callback security to normal operation.
1 All callback security calls will be direct connect regardless of whether the

password or phone number has the - character.

Default: 0

%S Command Speed Response

Description: Sets the modem to respond to AT commands at desired speeds.

Note: This command does not apply to the parallel build.

Syntax: AT%S<value>
Values: 0 Sets modem to respond to AT commands at all normal speeds.
1 AT commands accepted at 115200 bps only. Other speeds are ignored.
Default: 0

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Chapter 1 – AT Commands, S-Registers, and Result Codes

+A8E V.8 and V.8bis Operation Controls

Description: Use this command to set the control parameters for early call negotiation through V.8

and V.8bis. +A8E may also be used as an action command to reinitiate V.8 or V.8 bis

if an earlier attempt to use either protocol has failed. (ITU-T Recommendation V.251

(02/98) standardized this command. However, the controller-based command set

only includes partial support for the standard.)
On-Hook: If issued while the modem is on-hook, used to precondit ion V.8 and V.8bis

originating and answering operation. It is issued by the DTE before the Dial (D) or

Answer (A) command.
Off-Hook: If issued while the modem is off-hook, to (re)start V.8 or V.8bis

negotiation. For example, if initial V.8 negotiation failed, but subsequent T.30

negotiation indicated V.8 capability, this command may be used to initiate V.8

negotiation.
The ATD and ATA commands behave as specified in V.250, and +A8n indications

are not generated by the modem.
For subparameter values <v8o>=6 and <v8a>=5, the +A8I indications are issued

during the course of the V.8 session to notify the DTE when the relevant V.8 signals

are received.
<v8o> enables or disables DCE-controlled V.8 origination negotiation.

<v8a> enables or disables DCE-controlled V.8 answer negotiatio n.
<v8b> disables V.8 negotiation or sets it to DCE controlled or DTE controlled

negotiation.
<a8cf> sets the V.8 CI signal call function to the value specified.
The valid range for this parameter is 0 to FF, with a default of 0xC1.

Syntax: AT+A8E=<v8o>,<v8a>,<v8cf>,<v8b>
<v8o> Values: <v8o> Decimal number which enables/disables issuance of +A8x indications during

modem-controlled V.8 origination negotiation.

1 Enable DCE-controlled V.8 origination negotiation without +A8x

indications. (Default)

6 Enable DCE-controlled V.8 origination negotiation with +A8x indications.
<v8a> Values: <v8a> Decimal number which enables/disables issuance of +A8x indications during

modem-controlled V.8 answer negotiation.
1 Enable DCE-controlled V.8 answer negotiation without +A8x indications.
(Default)
5 Enable DCE-controlled V.8 answer negotiation with +A8x indications.

<v8b> Values: <v8b> Decimal number which enables/disables V.8bis negotiation.
0 Disable V.8 negotiation.
1 Enable DCE-controlled V.8bis negotiation. (Default)
2 Enable DTE-controlled V.8 negotiation.

<v8cf> Values <v8cf> Set the V.8 CI signal call function to the hexadecimal octet XY.
00 (Default)
21
C1

Reporting: +A8E? Reports current or selected values.
+A8E=? Reports supported parameter values.

Result Codes: OK if <v8o> = 1, 6 and <v8a> = 1, 5 and <v8cf> = 0 to FF and <v8b> = 0 to 2.
ERROR if <v8o> ≠ 1, 6 or <v8a> ≠ 1, 5 or <v8cf> ≠ 0 to FF or <v8b> ≠ 0 to 2.
OK if <signal> = 0–10 and <sig en> = 0, 1 and <msg en> = 0, 1 and <supp delay> =

0,1.

ERROR if <signal>

≠ 0 to 10 or <sig en> ≠ 0, 1 or <msg en> ≠ 0, 1 or <supp delay> ≠

0,1.

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+A8T Send V.8 bis Signal and/or Message

Description: Use this command to send a V.8 bis signal or message from the local DCE. This

command is only supported when V.80 is enabled.
Syntax: AT+A8T=<signal>,<1st message>,<2nd message>,<sig en>,<msg en>,<supp delay>
<signal> Values: 0 None

1 Initiating Mre.
2 Initiating MRd.
3 Initiating CRe, low power
4 Initiating CRe, high power
5 Initiating CRd
6 Initiating Esi
7 Responding MRd, low power
8 Responding MRd, high power
9 Responding CRd
10 Responding Esr
<sig_en> Values: 0 Enable detection of initiation signals. Default.
1 Enable detection or responding signals
<msg_en> Values: 0 Disable detection of messages. Default.
1 Enable detection of V.8 bis messages
<supp_delay> Values: 0 No delay inserted. Default.
1 Insert 1.5 second delay between transmitted V.8 bis signal and the subsequent

V.8 bis message
Reporting: +A8T? Reports current or selected values.

+A8T=? Reports supported parameter values.
Result Codes: OK if <signal> = 0 to 10 and <sig en> = 0, 1 and <msg en> = 0, 1 and <supp delay>

= 0,1.

ERROR if <signal> ≠ 0 to 10 or <sig en> ≠ 0, 1 or <msg en> ≠ 0, 1 or <supp delay> ≠

0,1.

+DCS Select V.42bis or V.44 Data Compression

Description: Use this command to configure the available compression algorithms. The <v42bis>

parameter enables or disables the V.42 bis and the <v44> parameter enables or

disables V.44. This command works in conjunction with the %C command and the

result of either the %C command or the +DCS command replaces the current data

compression configuration.
Syntax: AT+DCS=<v42bis>,<v44>
Values: 0,0 V.42bis and V.44 data compression are both disabled.

0,1 V.42bis is disabled; V.44 data compression is acceptable.
0,2 V.42bis is disabled; V.44 only when connected to a V.92 server.
1,0 V.42bis is acceptable; V.44 data compression is disabled.
1,1 V.42bis is acceptable; V.44 data compression is acceptable.
1,2 V.42bis is acceptable; V.44 only when connected to a V.92 server.

Reporting: +DCS? Reports current or selected values.
+DCS=? Reports allowed parameter values.

Result Codes: OK if <v42bis> = 0, 1 and <v44> = 0 to 2.
ERROR if <v42bis> ≠ 0, 1 or <v44> ≠ 0 to 2.

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+DR V.44 Data Compression Reporting

Description: Enables or disables the V.44 data compression report. If the compression report is

enabled, the +DR:<type> intermediate result code reports the current DCE-DCE data

compression type. It is issued after the Error Control Report (+ER) and before the

final result code (e.g., CONNECT).
Syntax: AT+DR=<value>
Values: 0 Disables the V.44 compressi on report.

1 Enables the V.44 comp ression report.
Default: 0

Reporting: +DR? Reports current or selected values.
+DR=? Reports supported parameter values.

Result Codes: OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1.
+DR: NONE Data compression not in use.
+DR: V42B V.42bis is in use in both directions.
+DR: V44 V.44 is in use in both directions.

+DS V.42bis Data Compression

Description: This extended-format compound parameter controls the V.42bis data compression

function if this function is provided in the modem.
Syntax: AT+DS=<direction>,<compr_neg>,<max_dict>,<max_string>
<direction> Values: Specifies the desired direction(s) of operation of the data compression function

from the DTE point of view.
0 Do not negotiate V.42 bis compression.
3 Modem accepts V.42 bis compression in both directions. Default.

<compr_neg> Values: Specifies whether or not the modem should continue to operate if the desired

result is not obtained.
0 Do not disconnect if V.42bis is not negotiated by the remote modem as

specified in <direction>. Default.

<max_dict> Values: Specifies maximum number of dictionary entries (2048 entries) negotiated. May

be used by the DTE to limit the code word size transmitted, based on its

knowledge of the nature of the data to be transmitted. Default = 2048.
<max_string> Values: Specifies maximum string length (32 bytes) to be negotiated. Default = 32.
Reporting: +DS? Reports current or selected values.

+DS=? Reports allowed parameter values.
Result Codes: OK

ERROR

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+DS44 V.44 Data Compression

Description: Controls the V.44 data compression function.
Syntax: AT+DS44=<direction>,<compression_negotiation>,<compatibility>,

<max_codewords_tx>, <max_codewords_rx>,<max_string_tx>,

<max_string_rx>,<max_history_tx>,<max_history_rx>
<direction> Values: Specifies the DTE direction of the data compression.

0 No compression.
3 Compression in both directions (default).

<max_codewords_tx> Values:
Specifies the maximum number of code words to be negotiated in the transmit

direction.
1024 Default.
256–2048 Maximum number of code words in transmit direction.

max_codewords_rx Values:
Specifies the maximum number of code words to be negotiated in the receive

direction.
1024 Default.
256–2048 Maximum number of code words in receive direction.

max_string_tx Values:
Specifies the maximum string length to be negotiated in the transmit direction.
255 Default.
31–255 Maximum string length in transmit direction.

max_string_rx Values:
Specifies the maximum string length to be negotiated in the receive direction.
255 Default.
31–255 Maximum string length in receive direction.

max_history_tx Values:
Specifies the maximum length of the history buffer to be negotiated in the transmit

direction.
5120 Default.
512–11008 History buffer size in transmit direction.

max_history_rx Values:
Specifies the maximum length of the history buffer to be negotiated in the receive

direction.
4096 Default.
512–11008 History buffer size in receive direction

Reports: +DS44=? Reports supported options.
Example: +DS44: (3, 0), (0), (0), (256-2048), (256-2048), (31-255), (31-255),

(512-11008), (512-11008).
+DS44? Reports current or selected options.
Example: +DS44: 3, 0, 0, 1024, 1024, 255, 255, 5120, 4096.

Result Codes: OK
ERROR

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Chapter 1 – AT Commands, S-Registers, and Result Codes

+EB Break Handling in Error Control Operation

Description: This extended-format compound parameter controls the break handling in V.42

operation. It accepts three numeric subparameters.
Syntax: AT+EB=<break_selection>,<default_length>
<break selection> Values:

0 Ignore break. Default.

1 Nonexpedited, nondestructive.

2 Expedited, nondestructive.

3 Expedited, destructive.
<default_length> Values:

10 ms to 90 ms Specify break length.
Reports: +EB=? Reports supported options.

+EB? Reports current or selected options.

+EFCS 32-bit Frame Check Sequence

Description: This extended-format numeric parameter controls the use of the 16-bit or 32-bit frame

check sequence (FCS) option in V.42.
Syntax: AT+EFCS=<value>
Value: 0 Sets the 32-bit frame check sequence to a 16-bit frame check sequence.
Reports: +EFCS? Reports current or selected options.

+EFCS=? Reports supported options.

+ER Error Control Report

Description: Use this command to enable or disable the error control report.
Syntax: AT+ER<value>
Values: +ER0 Error control reporting disabled (no +ER intermediate result code

transmitted). Default.

+ER1 Error control reporting enabled (+E R inte rmediate result code transmitted).
Reports: +ER? Reports current or selected options.

+ER=? Reports supported options.
+ER <type> The +ER <type> reported is the current (negotiated or renegotiated)

modem-modem error control type. If enabled, the intermediate result code is
transmitted at the point during error control negotiation (handshaking) at
which the modem has determined which error control protocol will be used (if
any), before the final result code (e.g., CONNECT) is transmitted.
Specifically, the +ER intermediate result code is issued after the modulation
report (+MCR and +MRR) and before the data compression report (+DR).

Result Codes: +ER: NONE Data compression not in use.
+ER: LAPM V.42 LAPM protocol is in use.

+ER: ALT V.42 alternative protocol is in use.
OK if <value> = 0, 1.
ERROR if <value> ≠ 0, 1.

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+ES Error Control Selection

Description: Use this command to select the error correction mode. If the modem is operating in

V.80 mode (synchronous buffered mode), and +ES=,,8, the +ES? will always return

+ES: 6,,8. The setting of this command overwrites the \N command, and the +ES

command is overwritten by the setting on a \N command.
Syntax: AT+ES=<orig_rqst>,<orig_fbk>,<ans_fbk>
Values: Values Combination Mode

+ES=1,0,1 Buffered mode
+ES=0,1,0 Direct mode
+ES=4,4,6 MNP or disconnect mode
+ES=3,3,5 LAPM or disconnect mode
+ES=4,0,6 MNP or buffered mode
+ES=3,0,2 LAPM, MNP, or buffered mode (Default)
+ES=2,0,2 LAPM or buffered mode
+ES=3,2,4 LAPM, MNP, or disconnect mode
+ES=,,8 V.42 sync buffer mode (V.80 enabled)
+ES=6,,8 V.42 sync buffer mode (V.80 enabled)
Reports: +ES? Reports current or selected options.

+ES=? Reports supported options.
Result Codes: OK
ERROR

+ESA Set Up Error Control Parameters

Description: Sets the control parameters for the DCE in Synchronous Access Mode.
Syntax: AT+ESA=<trans_idle>,<frame_idle>,<crc_type>,<nrzi_en>
Values: Values Combination Meaning

+ESA=0,,,,0,0,, Disables CRC generation and checking.
+ESA=0,,,,1,0,, Causes the DCE to generate a 16-bit CRC in the

transmit direction in framed sub-Mode and check the CRC in the receive direction.
<crc_type> Values: 0 Disable CRC generation and checking.
1 In framed submode, the 16-bit CRC specified in V.42 is generated by the DCE

in the transmit direction and checked by the DCE in the receive direction.
Result Codes: OK
ERROR

+ETBM Call Termination Buffer Management

Description: Sets the behavior of the modem upon call termination. Only +ETBM=0,0,0 is a valid

combination. This means that the modem will discard all the buffered data when the
call is terminated.

Syntax: AT+ETBM=<pending_TD>,<pending_RD>,<timer>
AT+ETBM=0,0,0

Values: <pending_TD> 0 specifies that disconnect will occur immediately and all buffered

transmit data will be discarded when the local DTE requests call
disconnection.

<pending_RD> 0 specifies that disconnect will occur immediately and all buffered

receive data will be discarded when the local DTE requests call
disconnection.

<timer> 0 specifies that the modem will not attempt to deliver the buffered

data before abandoning the attempt and discarding remaining
data.

Reports: +ETBM? Reports current or selected options.

+ETBM=? Reports supported options.
Result Codes: OK
ERROR

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Chapter 1 – AT Commands, S-Registers, and Result Codes

+FCLASS Fax Class Indication

Description: Use this command to set the modem service class. The service class determines if

the modem is in data, FAX, or voice mode.
Syntax: AT+FCLASS <Value>
Values: +FCLASS=0 Selects data mode.
+FCLASS=1.0 Selects Class 1.0 FAX mode.
+FCLASS=1 Selects Class 1 FAX mode.
+FCLASS=2 Selects Class 2 FAX mode.
+FCLASS=2.1 Selects Class 2.1 FAX mode.
+FCLASS=8 Selects voice mode.
Reports: +FCLASS? Reports current or selected options.
+FCLASS=? Reports supported options.
Result Codes: OK or ERROR

+GCAP Complete List of Capabilities Request

Description: Use this command to display the modem's supported capabilities. The +GCAP

command is an action command that always generates an OK result code.
Syntax: AT+GCAP

Sample Responses

+GCAP: +FCLASS, +MS, +ES, +DS, for a data modem that supports all capabilities

listed. Where:

+FCLASS (Class 1 and Class 2 facsimile DCE control)
+MS +M commands (Modulation Control: +MS and +M R commands)
+ES +E commands (Error Control: +ES, +EB, +ER, +EFCS, +ETBM)
+DS +D commands (Data Compression: +DS and +DR)

+GCI Country of Installation

Description: Use this command to set the modem country/region code.
Syntax: AT+GCI<country code>
Reports: +GCI? Reports current or selected options.
+GCI=? Reports supported options.
Result Codes: OK or ERROR

+GMI Manufacturer Identification Request

Description: Displays the modem product manufacturer.
Syntax: AT+GMI?
Reports: +GMI? Reports current or selected option.
Result Codes: OK when using the +GMI and +GMI? syntax.
ERROR when using the +GMI=? syntax.

+GMM Model Identification Request

Description: Displays the modem identity string and driver version number.
Syntax: AT+GMM? or AT+GMM=?
Reports: +GMM? Reports current or selected options.
+GMM=? Reports supported options.
Result Code: OK

+GMR Revision Request

Description: Displays the version of the modem code.
Syntax: AT+GMR? or AT+GMR=?
Reports: +GMR? Reports current or selected options.
+GMR=? Reports supported options.
Result Code: OK

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+IFC DTE-DCE Local Flow Control

Description: Use this command to select the local flow control method. The input parameters of

the +IFC command overwrite the settings of the \Q and \X<value> commands. The

reverse is also true. By modifying the settings of the \Q and \X<value> commands,

the +IFC command parameters are overwritten.
Syntax: AT+IFC=<DCE_by_DTE>,<DTE_by_DCE>
Values: +IFC=0,0 No flow control.

+IFC=1,1 Software flow control.
+IFC=2,2 Hardware flow control. (Default)

Reports: +IFC? Reports current or selected options.
+IFC=? Reports supported options.
Result Codes: OK

ERROR

+ILRR DTE-DCE Local Rate Reporting

Description: Use this command to display or hide the local rate report result code. If the rate

report is enabled, the reported <rate> is the current DTE-DCE rate. The rate report is

transmitted after any modulation, error control, or data compression reports, and

before the final result code (e.g., CONNECT).
Syntax: AT+ILRR<value>
Values: 0 Disables the local rate report. (Default)
1 Enables the local rate report.
Reports: +ILRR? Reports current or selected options.
+ILRR=? Reports supported options.
Result Codes: OK
ERROR

+IPR= Fixed DTE Rate

Description: Use this command to set the DTE to DCE transmission rate. There are twelve fixed

transmission rates used by the DTE to communicate with the DCE. These commands

select one of the predefined transmission rates. If a rate is entered which is not

supported, the transmission rate defaults to the next lower rate.
Syntax: AT+IPR=<DTE rate>
Values: +IPR=0 Automatic rate detection. (Default)

+IPR=110 100 bits/s
+IPR=300 300 bits/s
+IPR=600 600 bits/s
+IPR=1200 1200bits/s
+IPR=2400 2400 bits/s
+IPR=4800 4800 bits/s
+IPR=9600 9600 bits/s
+IPR=14400 14400 bits/s
+IPR=19200 19200 bits/s
+IPR=38400 38400 bits/s
+IPR=57600 57600 bits/s
+IPR=115200 115200 bits/s

Reports: +IPR? Reports current or selected options.
+IPR=? Reports supported options.

Result Code: OK

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+ITF= Transmit Flow Control Threshold

Description: Use this command to set the flow control thresholds. The <off> parameter represent

the off signal threshold in octets. When this threshold is reached the DCE generates

a flow off signal. The <on> parameter represents the on signal threshold in octets.

When the volume of data resident on the DCE goes below this value the DCE

generates a flow on signal.
Syntax: AT+ITF=<off>,<on>

Reports: +ITF? Reports current or selected options.
+ITF=? Reports supported options.

Result Code: OK
ERROR

+MR Modulation Reporting Control

Description: Use this command to hide or display the modulation report. When the modulation

report is enabled, the DCE transmits the +MRR: <rate>, <rx_rate> and the

+MCR:<carrier> intermediate result codes to the DTE.
The <carrier> reported is the current modulation; for example, V.34.
The <rate> reported is the transmit rate in bits per second or is zero if negotiation

fails.
The <rx_rate> is the receive channel rate and is only reported when different receive

and transmit rates have negotiated.
The intermediate result codes are transmitted after the modulation and the rate have

been determined and before any error control or data compression reports or the final

result code (e.g., CONNECT) is transmitted.
Syntax: AT+MR=<value>
Values: +MR=0 Turns off the modulation report.

+MR=1 Turns on the modulation report.
Reports: +MR? Reports current or selected options.
+MR=? Reports supported options.

Result Code: OK
ERROR

+MS Modulation Selection

Description: Sets the modem’s modulation, the modulation minimum and maximum transmission

rates, and the status of automatic modulation negotiation (automode). The <carrier>,

<min_rate>, and <max_rate> parameters define the modulation and its minimum and

maximum transmission rates. <min_rx_rate> and <max_rx_rate> define the minimum

and maximum reception rates. The minimum transmission and reception rates are

always set to 0.
The <automode> parameter enables or disables automatic modulation negotiation. If

a subsequent +MA command is not provided, the automode parameters are

constrained by the modulation set by the <carrier> parameter. The +MA command

can further restrict the automatic modulation negotiation settings but it cannot set a

modulation that is higher than the modulation set by the +MS command.
Once a modulation is selected by the +MS command, the autorate in both directions

and the automode is activated unless <max_rate> is specified by in the command.
The settings of this command overwrite the settings of S28 and S37. Likewise,

changes to these registers overwrite the settings of the +MS command

Continued on next page

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Syntax: ATMS=<carrier>,<automode>,<min_rate>,<max_rate>,<min_rx_rate>, <max_rx_rate>
<carrier> Values: V92 V.92 (default)

V90 V.90
V34 V.34
V32B V.32bis
V32 V.32
V22B V.22bis
V.22 V.22
Bell212A Bell 212A*

V23C V.23, constant carrier, asymmetric FDM
V21 V21
Bell103 Bell 103*

*The +MS command was standardized by ITU-T recommendation V.250. However,
the standard command does not include the additional functionality provided by the
Bell212A and Bell103 values of the <carrier> parameter.

<automode> Values: Automatic modulation negotiation is enabled or disabled by <automode>.

However, if a value is specified for the <max_rate> then, automatic rate selection

is disabled and the modem will attempt to connect at the specified rate.
0 Disables automode.
1 Enables automode. (Default)
<max rate> Values: The <max_rate> specifies the highest connections rate for the DCE.
31200 Determined by modulation selected in <carrier>. (Default)
300-56000 Value limited by modulation selected <carrier>.

<max rate> for each <carrier>.
V34 2400 bits/s—33600 bits/s in steps of 2400 bits/s.

V32bis 4800 bits/s—19200 bits/s in steps of 2400 bits/s.
V32 4800 bits/s—14400 bits/s in steps of 2400 bits/s.
V22bis 2400 bits/s.
V22 2200 bits/s.
V23C, Bell212A 1200 bits/s.
V.21, Bell103 300 bits/s.

Valid <max rate> Range
56000 Determined by modulation selected in <carrier>. (Default)
300-56000 Value limited by modulation selected <carrier>.

Valid <max rx rate> Value for each <carrier>

V92 28000 bits/s—56000 bits/s in steps of 1333 bits/s
V90 28000 bits/s—56000 bits/s in steps of 1333 bits/s
V34 2400 bits/s—33600 bits/s in steps of 2400 bits/s
V32bis 4800 bits/s—19200 bits/s in steps of 2400 bits/s
V32 4800 bits/s—14400 bits/s in steps of 2400 bits/s
V22bis 2400 bits/s
V22 2200 bits/s
V23C, Bell212A 1200 bits/s
V.21, Bell103 300 bits/s

Reports: +MS? Reports current or selected options.
+MS? Reports supported options.
Result Code: OK
ERROR

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Chapter 1 – AT Commands, S-Registers, and Result Codes

$D DTR Dialing

Description: Dials the number in a memory location.
Syntax: AT$D<value>
Values: 0 Disables DTR dialing.
1 Dials the number in memory location 0 when DTR goes high.
Default: 0
Result Codes: OK
ERROR

$EB Asynchronous Word Length

Description: Enables 10-bit or 11-bit mode.
Syntax: AT$EB<value>
Values: 0 Enables 10-bit mode.
1 Enables 11-bit mode.
Default: 0

$LB Long Break

Description: Sets the length of a break sent to the DTE by the modem when received from the

remote side.
Note: This command does not apply to the parallel build.
Syntax: AT$LB=<value>
Values: 0-255 in 10 ms increments
Default: 30 (300 ms break)

$MB Online BPS Speed

Description: Selects speed in bits per second.
Syntax: AT$MB<value>
Default: 28,800
Values: 75 Selects CCITT V.23 mode
300 Selects 300 bps on-line
1200 Selects 1200 bps on-line
2400 Selects 2400 bps on-line
4800 Selects 4800 bps on-line
9600 Selects 9600 bps on-line
14400 Selects 14400 bps on-line
19200 Selects 19200 bps on-line
28800 Selects 28800 bps on-line
33600 Selects 33600 bps on-line

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Chapter 1 – AT Commands, S-Registers, and Result Codes

$RP Ring Priority vs. AT Command Priority

Description: Sets the ring priority vs. the AT command priority.

Note: This command does not apply to the parallel build.

Syntax: AT$RP<value>
Values: 0 The AT command will have priority over the ring. S1 will be reset to 0 if an AT

command is received. This command is storable to memory.

1 The ring will have priority over the AT command. S1 will increment even if an

AT command and ring are received together and the incoming call will be
answered when S1 is equal to S0. Default.

Note: SocketModems do not detect ring cadence of TelTone telephone line

simulators as a valid ring

$SB Serial Port Baud Rate

Description: Sets the serial port baud rate.
Syntax: AT$SB<value>
Values: $SB300 Sets serial port to 300 bps
$SB1200 Sets serial port to 1200 bps
$SB2400 Sets serial port to 2400 bps
$SB4800 Sets serial port to 4800 bps
$SB9600 Sets serial port to 9600 bps
$SB19200 Sets serial port to 19200 bps
$SB38400 Sets serial port to 38400 bps
$SB57600 Sets serial port to 57600 bps (Default)
$SB115200 Sets serial port to 115200 bps
$SB230400 Sets serial port to 230400 bps

+VDR Distinctive Ring Report

Description: Enables reporting of ring cadence information to the DTE and specifies the minimum

ring cadence that will be reported.
The report format is one line per silence period and one line per ring period. The

length of the silence period is in the form DROF=number in units of 100

ms<CR><LF>, and the length of the ring is in the form DRON=number in units of 100

ms<CR> <LF>. The modem may produce a Ring event code after the DRON

message if enabled by the y parameter. The y parameter must be set to a value

equal to or smaller than the expected ring cadence.
Syntax: AT+VDR=<value x>, <value y>
Values: x = 0, 1 Distinctive Ring report control. Default = 0.
y = 0–255 Minimum ring interval in 100 ms units. Default = 0.
+VDR=0, N/A Disables Distinctive Ring cadence reporting.
+VDR=1, 0 Enables Distinctive Ring cadence reporting. Other call progress

result codes (including RING) are reported as normal.

+VDR=1, >0 Enables Distinctive Ring cadence reporting. The RING result code is

reported after the falling edge of the ring pulse (i.e., after the DRON

report).
Reports: +VDR=? Displays the allowed values.
+VDR? Displays the current value.

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#P Set 11-bit Parity

Description: Sets 11-bit parity.
Syntax: AT#P<value>
Values: 0 No parity.
1 Odd parity.
2 Even parity.
Default: 2

#S Enter Setup Password

Description: Sets the remote configuration password.
Syntax: AT#S<password>
Values: password (1–8 characters, case sensitive)
Default: MTSMODEM

#S= Store Setup Password

Description: Stores a new remote configuration setup password.
Syntax: AT#S=x
Values: x= password (1–8 characters, case sensitive)

%%%ATMTSMODEM<CR> Remote Configuration Escape Sequence

Description: Initiates remote configuration mode while online with remote modem. The remote

configuration escape character (%) is defined in register S9.
Syntax: %%%ATMTSMODEM<CR>
Values: N/A

+VCID= Caller ID Selection

Description: Enables Caller ID detection and configures the reporting and presentation of the

Caller ID data that is detected after the first ring. The reported data includes the date

and time of the call, the caller's name and number, and a message. Set S0=2.
Syntax: AT+VCID=<value>
Values: +VCID=0 Disables Caller ID
+VCID=1 Enables Caller ID with formatted data
+VCID=2 Enables Caller ID with unformatted data
+VCID=? Displays the allowed values
+VCID? Displays the current value
Default: 0

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Chapter 1 – AT Commands, S-Registers, and Result Codes

Callback Security Commands

Note: Callback Security Commands do not apply to the parallel build.

#CBA Callback Attempts

Description: Sets the number of callback attempts that are allowed after passwords have been

exchanged between modems.
Syntax: AT#CBA<value>
Values: 1–255
Default: 4

#CBD Callback Delay

Description: Sets the length of time (in seconds) that the modem waits before calling back the

remote modem.
Syntax: AT#CBD<value>
Values: 0–255
Default: 15

#CBF? Callback Failed Attempts Display

Description: Requests the number of failed callback passwords since reset or power-up. This

number can be stored to nonvolatile memory using the &W command.
Syntax: AT#CBF?
Values: N/A

#CBFR Callback Failed Attempts Reset

Description: Resets the number of failed callback passwords to 0. This does not reset the number

stored in nonvolatile memory.
Syntax: AT#CBFR
Values: N/A

#CBI Local Callback Inactivity Timer

Description: Sets the time (in minutes) that the modem waits for a command before forcing the

user to enter the setup password again.
Syntax: AT#CBI<value>
Values: 1–255
Default: 20

#CBN Store Callback Password

Description: Sets the callback security password for the y memory location. The password must

have 6 to 10 characters, and cannot include the + or - characters.
Syntax: AT#CBN<y=x>
Values: y = 0–29
x = password
Defaults: None

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Chapter 1 – AT Commands, S-Registers, and Result Codes

#CBP Callback Parity

Description: Sets parity for the callback security messages.
Syntax: AT#CBP<value>
Values: 0 No parity.
1 Odd parity.
2 Even parity.
Default: 0

#CBR Callback Security Reset

Description: Clears the password and phone number in the y memory location.
Syntax: AT#CBR<value>
Values: 0–29
Default: None

#CBS Callback Enable/Disable

Description: Enables or disables callback.
Syntax: AT#CBS<value>
Values: 0 Disables callback security. Default.
1 Enables local and remote callback security.
2 Enables remote callback security only.
3 Disables callback security until local hang-up or reset.

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Chapter 1 – AT Commands, S-Registers, and Result Codes

S-Registers

Certain modem values, or parameters, are stored in memory locations called S-Registers. Use the S
command to read or to alter the contents of S-Registers (see previous section).

Register Unit Range Default Description
S0 1 ring 0, 1–255 1 Sets the number of rings until the modem answers. ATS0=0

disables auto answer completely.

S1 1 ring 0–255 0 Counts the rings that have occurred.
S2 decimal 0–127 43 (+) Sets ASCII code for the escape sequence character.
S3 decimal 0–127 13 (^M) Sets the ASCII code for the carriage return character.
S4 decimal 0–127 10 (^J) Sets the ASCII code for the line feed character.
S5 decimal 0–32 8 (^H) Sets the ASCII code for the backspace character.

33–127 Values greater than 32 disable backspace.
S6 seconds 2–65* 2* Sets the time the modem waits after it goes off-hook before it

begins to dial the telephone number.

S7 seconds 35-65* 50* Sets the time the modem waits for a carrier signal before

aborting a call. Also sets the wait for silence time for the @ dial
modifier.

S8 seconds 0–65 2 Sets the length of a pause caused by a comma character in a

dialing command.

S9 decimal 0, 1–127 37 (%) Sets ASCII code for remote configuration escape character.

S9=0 disables remote configuration.

S10 100 ms 1–254 20 Sets how long a carrier signal must be lost before the modem

disconnects.

S11 1 ms 50–150* 95* Sets spacing and duration of dialing tones.
S24 secs 0, 5-65 0 Sets the timer to control sleep mode. Default of 0 = Off.
S28 decimal 0, 1–255 1 0 disables, 1–255 enables V.34 modulation.
S30 1 minute 0, 1–255 0 Sets the length of time that the modem waits before

disconnecting when no data is sent or received. A value of
zero disables the timer. See also the \T command

S35 decimal 0–1 1 0 disables, 1 enables the V.25 calling tone, which allows

remote data/fax/voice discrimination.

S36 decimal 0–7 7 Specifies the action to take in the event of a negotiation failure

when error control is selected. (See S48.)

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S37 decimal 0–19 0 Sets the maximum V.34 “upstream” speed at which the

modem attempts to connect.
0 = maximum speed
1 = reserved
2 = 1200/75 bps
3 = 300 bps
4 = reserved

5 = 1200 bps

6 = 2400 bps

7 = 4800 bps

8 = 7200 bps

9 = 9600 bps

10 = 12000 bps

11 = 14400 bps

12 = 16800 bps

13 = 19200 bps

14 = 21600 bps

15 = 24000 bps

16 = 26400 bps

17 = 28800 bps

18 = 31200 bps

19 = 33600 bps
S38 decimal 0–23 1 Sets “downstream” data rate where V.90 provides rates of

28,000 to 56,000 bps in increments of 1,333 bps.
0 = V.90 disabled

1 = V.90 auto rate

2 = 28,000 bps

3 = 29,333 bps

4 = 30,666 bps

5 = 32,000 bps

6 = 33,333 bps

7 = 34,666 bps

8 = 36,000 bps

9 = 37,333 bps

10 = 38,666 bps

11 = 40,000 bps

12 = 41,333 bps

13 = 42,666 bps

14 = 44,000 bps

15 = 45,333 bps

16 = 46,666 bps

17 = 48,000 bps

18 = 49,333 bps

19 = 50,666 bps

20 = 52,000 bps

21 = 53,333 bps

22 = 54,666 bps

23 = 56,000 bps
Upstream data rates: Upstream V.90 data rates are 4800 to

33,600 bps in 2400 bps increments.
S43 decimal 0–1 1 For testing and debugging only. Enables/disables V.32bis

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start-up auto mode operation. 0 = disable; 1 = enable.

Chapter 1 – AT Commands, S-Registers, and Result Codes

S48 decimal 7 or 128 7 Enables (7) or disables (128) LAPM negotiation . The following

table lists the S36 and S48 configuration settings for certain

types of connections.

S36=0, 2 LAPM or hang up Do not use
S36=1, 3 LAPM or async Async
S36=4, 6 LAPM, MNP, or hang up MNP or hang up
S36=5, 7 LAPM, MNP, or async MNP or async

S48=7 S48=128

S89 seconds 0, 5–65 0 Sets the length of time in the off-line command mode before

the modem goes into standby mode or “sleep mode ”. A value

of zero prevents standby mode; a value of 1–4 sets the value

to 5. Standby mode (sleep mode or low power mode) is

controlled by S89. It programs the number of seconds of

inactivity before the modem will go to sleep. The default value

is 0. A value of 0 disables standby mode. The modem will

wake on an incoming ring or an AT command.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 39

Chapter 1 – AT Commands, S-Registers, and Result Codes

Result Codes

In command mode your modem can send responses called Result Codes to your computer. Result
codes are used by communications programs and can also appear on your monitor.

Verbose Description

Terse

0 OK Command executed
1 CONNECT Modem connected to line
2 RING Ring signal detected
3 NO CARRIER Carrier signal lost or not detected
4 ERROR Invalid command
5 * CONNECT 1200 Connected at 1200 bps
6 NO DIALTONE No dial tone detected
7 BUSY Busy signal detected
8 NO ANSWER No answer at remote end
9 CONNECT 75 Connected at 75 bps
10* CONNECT 2400 Connected at 2400 bps
11* CONNECT 4800 Connected at 4800 bps
12* CONNECT 9600 Connected at 9600 bps
13* CONNECT 14400 Connected at 14400 bps
14* CONNECT 19200 Connected at 19200 bps
18 CONNECT 57600 Connected at 57600 bps
24* CONNECT 7200 Connected at 7200 bps
25* CONNECT 12000 Connected at 12000 bps
26 CONNECT 16800 Connected at 16800 BPS
28 CONNECT 38400 Connected at 38400 bps
40* CONNECT 300 Connected at 300 bps
55* CONNECT 21600 Connected at 21600 bps
56* CONNECT 24000 Connected at 24000 bps
57* CONNECT 26400 Connected at 26400 bps
58* CONNECT 28800 Connected at 28800 bps
59* CONNECT 31200 Connected at 31200 bps
60* CONNECT 33600 Connected at 33600 bps
70 CONNECT 32000 Connected at 32000 bps
71 CONNECT 34000 Connected at 34000 bps
72 CONNECT 36000 Connected at 36000 bps
73 CONNECT 38000 Connected at 38000 bps
74 CONNECT 40000 Connected at 40000 bps
75 CONNECT 42000 Connected at 42000 bps
76 CONNECT 44000 Connected at 44000 bps
77 CONNECT 46000 Connected at 46000 bps
78 CONNECT 48000 Connected at 48000 bps
79 CONNECT 50000 Connected at 50000 bps
80 CONNECT 52000 Connected at 52000 bps
81 CONNECT 54000 Connected at 54000 bps
82 CONNECT 56000 Connected at 56000 bps
83 CONNECT 58000 Connected at 58000 bps
84 CONNECT 60000 Connected at 60000 bps
86 CONNECT 16800 Connected at 16800 bps
87 CONNECT 115200 Connected at 115200 bps
88 DELAYED Delay is in effect for the dialed number
89 BLACKLISTED Dialed number is blacklisted
90 BLACKLIST FULL Blacklist is full
91 CONNECT 230400 Connected at 230400 bps
100 CONNE CT 28000 Connected at 28000 bps
101 CONNE CT 29333 Connected at 29333 bps
102 CONNE CT 30666 Connected at 30666 bps

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Chapter 1 – AT Commands, S-Registers, and Result Codes

103 CONNE CT 33333 Connected at 33333 bps
104 CONNE CT 34666 Connected at 34666 bps
105 CONNE CT 37333 Connected at 37333 bps
106 CONNE CT 38666 Connected at 38666 bps
107 CONNE CT 41333 Connected at 41333 bps
108 CONNE CT 42666 Connected at 42666 bps
109 CONNE CT 45333 Connected at 45333 bps
110 CONNE CT 46666 Connected at 46666 bps
111 CONNE CT 49333 Connected at 49333 bps
112 CONNE CT 50666 Connected at 50666 bps
113 CONNE CT 53333 Connected at 53333 bps
114 CONNE CT 54666 Connected at 54666 bps
115 CONNE CT 25333 Connected at 25333 bps
116 CONNE CT 26666 Connected at 26666 bps

When the extended result code configuration is enabled, one of the following codes is append ed to the
result code depending on the type of error control connection:

V42bis – V.42 error control (LAP-M) and V.42bis data compression
V42 – V.42 error control (LAP-M) only
MNP5 – MNP 4 error control and MNP 5 data compression
MNP4 – MNP 4 error control only
NoEC – No error control protocol).

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 41

Chapter 4 – Voice Commands

Chapter 4 – Voice Commands

Introduction

Important Note:

Voice commands do not apply to the SMI build.

This chapter describes +V command support. The +V Command standard IS-101 Voice Control Interim
Standard for Asynchronous DCE (prepared by the TIA Technical Subcommittee TR29.2 on Facsimile
Digital Interface) defines the commands that a PC user may issue to configure and control a
voice/fax/data modem and the responses (result codes) that the voice/fax/data modem may issue in
response to those commands.

The +V commands and responses provide control of the following services:

• Recording and playback of digitized voice.

• Generation and detection of DTMF and other tones.

• Switching between voice, fax, and data modes.

• Control-related functions.

The Voice mode has three states, which correspond to the direction of voice data flow:

Voice command state (event reports only; no data transfers).

Voice transmit state (digitized, half-duplex voice data transfers from PC to modem).
Voice receive state, (digitized, half-duplex voice data transfers from modem to PC).

The modem supports three levels of voice service: Service Levels A, B, and C. Service Level A provides
the lowest level of services. Service level A performs operations and detects events as follows: Voice
transmit, Voice receive, and DTMF generation and Single tone generation. The following events (Result
Codes) are reported: 3, 4, 5, 6, 9, 10, 18, 19, 23, 25.

Service Level B provides an optionally greater amount of services, providing DTMF and facsimile calling
tone detection during voice transmits in addition to Service Level A. Service Level B provides event­reporting similar to Service Level A, but with added event reporting states (e.g., fax calling in transmit
state in addition to reporting in command state).

Service Level C provides the highest service level with the addition of facsimile calling tone and Busy
detection during receives, Dial Tone detection, and double-tone detection. An example of event detection
in a Service Level C modem is shown below:

AT+VEM=?
"C"
0A000100
0E601800
1A803840
OK

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 42

Voice S-Register Summary

Voice mode S-Register changes are outlined below.

Chapter 4 – Voice Commands

S-Register

S0 Automatic answer is disallowed in Voice mode.
S7 Wait for Carrier After Dial. Default is 60 seconds. In Voice mode, S7 contains the

S10 Automatic disconnect is disallowed in Voice mod e.

Description

maximum amount of time that the modem will wait during Call Origination, all the time
detecting for ring backs, before assuming that the remote station will not go off hook.

Voice Commands

The +V Voice enhancements are implemented with AT+V (for Voice) comman ds, as well as changes to
several existing commands.

In general, the modem does not accept Data mode (+FCLASS=0) commands or Fax mode (+FCLASS=1,

1.0, 2, 2.0, 2.1) commands when in Voice mode (+FCLASS=8).

Commands That Change for Voice Mode
Support

Command: Description
A Disallowed in Voice mode.
D Causes the modem to Dial assuming +VLS=2 if +VLS=0 when the ATD command

was entered.

H Values greater than 0 disallowed in Voice mode.
I Disallowed in Voice mode.
M Disallowed in Voice mode.
O Disallowed in Voice mode.
Q Disallowed in Voice mode.
X Disallowed in Voice mode.
Z Reset modem.
&D &D1 is disallowed in Voice mode.
+FCLASS=8 Places the modem in Voice mode.
+FCLASS= New values are added for Voice mode.
+FCLASS=? New values are added for Voice mode.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 43

Chapter 4 – Voice Commands

Voice +V Commands Detail

+FCLASS= 8 Select Voice Mode

Description: The +FCLASS= command selects voice mode.

+VNH Automatic Hang-Up Control

Description: Enables or disables automatic hang-up.
Syntax: AT+VNH=<hook>
Values: <hook>
+VNH=0 Enables automatic hang-ups as in non-Voice modes (such as

hanging up the phone when the modem does not detect a data

carrier within a given time interval).
+VNH=1 Disables automatic hang-ups in non-Voice modes.
+VNH=2 Disables automatic hang-ups in non-Voice modes. The modem

performs only a "logical" hang up (i.e., returns the OK result code).

Reports: +VNH? Displays current or selected values.
+VNH=? Displays list of supported values.
Result Codes: OK if command accepted.
ERROR if parameter is out of range.

+VIP Initialize Voice Parameters

Description: The +VIP command causes the modem to initialize all Voice parameters to the

factory default settings.
Syntax: AT+VIP
Values: None

+VRX Enter Voice Receive State

Description: Start voice reception.
Syntax: AT+VRX
Values: None
Result Codes: OK
ERROR if not in voice mode.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 44

Chapter 4 – Voice Commands

+VTS Send Voice Tone(s)

Description: This command causes the modem to send DTMF digit or hookflash tones with the

duration specified by +VTD, to send DTMF digit or hookflash tone duration specified

by this command, or to send single or dual tone frequencies with duration specified

with this command.
Syntax: AT+VTS=<string>

Values: <string> The tone generation string consists of elements in a list where each

element is separated by commas. Each element can be:

1. A single character which the modem interprets as a DTMF digit (0–9,

#, *, and A–D) or hookflash (!), with a duration given by the +VTD
command.

2. A 3-element string enclosed in square brackets "[freq1,freq2,dur]",

which the modem interprets as a general dual tone and duration
(dur) selection.

3. A 2-element string enclosed in curly braces "{X,dur}", which the

modem interprets as a DTMF digit ((0–9, #, *, and A–D) or hookflash
(!), with a duration (dur) different than that given by the +VTD

command.
Missing parameters are assumed to be the default value. Unspecified
values always default to 0 for frequencies, DTMF * for DTMF tones, and
+VTD for duration. The omission of commas (and associated
subparameters) is valid.

Result Codes: OK if the PC accepts the command.
ERROR if the modem encountered an error in parsing the subparameter or if the

selected frequency is out of range.
Example: Using the +VTS command for tone generation without using any null eleme nts:
AT=VTS=1,2,[1000,1300,50],{*6},{800,1300,50},9

The above string will perform as follows:

1. Play DTMF 1 with a duration given by the +VTD command.

2. Play DTMF 2 with a duration given by the +VTD command.

3. Play tone pair at 1000 Hz and 1300 Hz with a duration of 500 ms.

4. Play DTMF * with a duration of 60 ms.

5. Play tone pair at 800 Hz and 1300 Hz with a duration of 500 ms.

6. Play DTMF 9 with a duration given by the +VTD command.

Reports: +VTS=? Reports Frequency Support. Reports the current frequency range in the

form <freq1>,<freq2>,<dur> , where <freq1> is the first frequency range,<freq 2> is

the second frequency range, and<dur> is the duration range for the square brackets

and curly braces constructs. The units are in 0.01 seconds. The range of valid <dur>

values is that of the +VTD command.

Example: In the lines below, the modem responds to the +VTS=? command by

reporting that it supports two frequencies, both in the range of 200-3300 Hz, and

supports a duration range from 0 to 5 seconds.

AT+VTS=?

(200-3300), (200-3300), (0-500)
OK

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Chapter 4 – Voice Commands

+VTX Start Voice Transmission Process

Description: Starts the voice transmission process. The PC sends the data in the format of the

previously entered +VSM command, using the flow control method selected by the

+FLO command. The voice data is buffered to withstand gaps of missing data from

the PC. If the modem does not have any current voice data, the modem sends

silence over to the analog destination until the PC provides more voice data. The

modem returns the OK result code and returns to Command mode after the modem

has completely transmitted its buffer contents. The Inactivity Timer can be used to

terminate the transmit data state, after which the modem returns to Command mode.
Syntax: AT+VTS
Result Codes: OK on completion of transmission.
CONNECT if the modem accepts the command.
ERROR if the modem is not connected to at least one off-hook Telco line or one non-

Telco device.

+VGR Voice Gain for Received Voice Samples

Description: Sets the gain for the received voice samples. Receive gain values larger than 128

indicate a larger gain than nominal, and values smaller than 128 indicate a gain

smaller than nominal. The modem may limit the receive gain to a narrower range,

such as from 120 to 136, or from 120 to 128. The value 0 is reserved for modem

automatic gain control (AGC).
Syntax: +VGR=<gain>
Values: 0 (this is the only valid value) Selects automatic gain control.
Result Codes: OK if <gain>=0
ERROR if <gain> is not 0 or if not in voice mode.
Reports: +VGR? Displays current or selected values.
+VGR=? Displays list of valid values supported.

+VGT Set the Volume for Transmitted Voice Samples

Description: Sets the volume control, either by attenuating or amplifying the signal for the

transmitted voice samples. Values larger than 128 indicate a larger gain than

nominal, and values smaller than 128 indicate a gain smaller than nominal. The

modem may limit the receive gain to a narrower range, such as from 120 to 136, or

from 120 to 128. The value 0 is reserved for modem automatic volume control (AVC).

Note: The modem will limit the transmit level over the Telco lines, regardless of the

current +VGT setting, to that permitted by CFR FCC Rules Part 68 – Subpart

D.
Syntax: +VGT=<level>
Result Codes: OK if the modem accepts the command
ERROR if the parameter is out of range.
Reports: +VGT? Displays current or selected values.
+VGT=? Displays list of valid values supported.

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Chapter 4 – Voice Commands

+VIT Set DTE/DCE Inactivity Timer

Description: Sets the modem's initial value for the PC/Modem Inactivity Timer. The units are in 1.0

seconds. The PC can disable the Inactivity Timer by using a value of 0 (+VIT=0).

The Inactivity Timer serves to ensure that the PC does not leave the modem in a

state where it is not accessible by voice-unaware software. The Inactivity Timer is
activated when the PC selects the voice fixed-rate. The timer expires if the flow of
data from the PC to the modem stops (in both Voice Command mode and Data
mode) for a specified amount of time.

When this timer expires, the modem switches to Data mode with autobauding. By

switching to autobauding (and Data mode), the PC is allowed voice-unaware
software to recover control of the modem in the event of catastrophic failure that does
not result in a modem power down. It is recommended that the PC software leave the
modem in autobauding (and Data mode), and use the Inactivity Timer only as
needed. Leaving the modem in autobauding is an extra measure to prevent
confusion from voice-unaware software accessing the modem in Voice mode at a
fixed PC/modem interface rate. You can use the H command to switch to
autobauding and Data mode automatically. In Voice mode, the modem does not
allow the auto answer feature, since this feature does not allow the PC to set the
modem in Voice mode before answering the phone.

Syntax: AT+VIT=<timer>
Values: <timer>
0 Disables the timer. Default.
0-255 Timer set in units of 1.0 seconds.
Result Codes: OK if <timer> = 0-255.
ERROR if the parameter is out of range or if not in voice mode.
Reports: +VIT? Displays current or selected values.
+VIT=? Displays list of valid values supported.

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Chapter 4 – Voice Commands

+VLS Select Analog Source/Destination

Description: Selects one or more source/destination devices for the analog data to be transmitted.

The parameter <label> identifies each of the supported analog so urce/destination
hardware devices. Codes, called "primitives", are provided to describe which voi c e
I/O device(s) are components in a possible hardware configuration. The codes are
grouped to help define and label 16 common hardware configurations. Each code,
except "L" and "T" is followed by an ASCII 0 code (20 hex). Two codes can be

concatenated to define a possible analog source/destination hardware configuration.
Syntax: AT+VLS=<label>
Values: <label> A decimal number corresponding to the selected analog source/destination

hardware configuration:

<label>

Result Codes: OK if command accepted.
ERROR if the <label> parameter is out of range or if the modem cannot service the

<label> parameter requested. (Continued on next page).

Code(s)* Description

0 none Modem on-hook. Local phone connected to Telco. Default.
1 T Modem off-hook, and connected to Telco. Local phone

provided with power to detect hook condition.
2 L Modem off-hook. Local phone connected to modem.
3 LT Modem off-hook. Local phone connected to Telco. Modem

connected to Telco.
4 S Internal speaker connected to the modem. Modem is on-hook.

Local phone connected to Telco.
5 ST Internal speaker connected to Telco. Modem off-hook. Modem

connected to Telco. Local phone provided with power to detect

hook condition.
6 M Internal microphone connected to modem. Modem is on-hook.

Local phone connected to Telco.
7 MST Internal microphone and internal speaker connected to Telco.

Squelching active. Modem is off-hook, and connected to Telco.

Local phone provided with power to detect hook condition.
8 S1 External speaker connected to modem. Modem is on-hook.

Local phone connected to Telco.
9 S1T External speaker conne cte d to Telco. Modem is off-hook and

connected to Telco. Local phone provided with power to detect

hook condition.
10 MS1T Internal microphone and external speaker connected to Telco.

Squelching active. Modem is off-hook, and connected to Telco.

Local phone provided with power to detect hook condition.
11 M1 External microphone connected to modem. Modem is off-

hook. Local phone connected to Telco.
12 M1ST External microphone and internal speaker connected to Telco.

Squelching active. Modem is off-hook, and connected to Telco.
Local phone provided with power to detect hook condition.
13 M1S1T External microphone and external speaker connected to Telco.

Squelching active. Modem is off-hook, and connected to Telco.

Local phone provided with power to detect hook condition.
14 H External microphone and speaker combination (handset or

headset) connected to modem. Modem is off-hook. Local

phone connected to Telco.
15 HT External microphone and speaker combination (headset or

handset) connected to modem. Modem is off hook, and

connected to Telco. Local phone provided with power to detect

hook condition.

*Codes: L Local Phone
T Telephone Line
M Internal Microphone
M1 External Microphone
S Internal Speaker
S1 External Speaker
H External Microphone and Microphone combination (handset or headset)

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Chapter 4 – Voice Commands

Reports: +VLS? Displays current or selected values.
+VLS=? +VLS=? displays the modem's current source and destination device

information for the analog data to be transmitted. Refer to the +VLS=
<label> command for label code and description information. Note that
the +VEM command contains more information about event reporting.
Example: In the lines below, the modem reports that it supports only a
Telco line at Service Level C.
AT+VLS=?

0,"",0A0001000,0E601800,1A803840
1, "T", 0A0001000,0E601800,1A803840

Response: <label>,<devices>,transmit event>,<receive event>,<idle
event>

<label> Identifies the modem analog source/destination

hardware configuration
<devices> a <string constant> made up of Primitives.
<xxxx event> <transmit event>,<receive event>, and <idle event>

subparameters are the DCE event reporting

capabilities for the Voice Transmit State, Voice

Receive State, and the Voice Command State

respectively. Each of the event reporting

subparameters is a hex number that represents an

event bit field.

+VRA Ringback Goes Away Timer

Description: Sets the length of time the modem will wait between ringbacks during a call

origination before the modem can assume that the remote device has gone off-hook.
Syntax: AT+VRA=<interval>
Values: <interval> A decimal number (0–255) specifying the silence interval time in units of

0.10 seconds between the end of one ring interval and the start of the
next ring interval. A value of 0 forces the modem to report the OK result
code and immediately after the first ringback. The range is 0.1 to 25.5

seconds for <interval>=1 to 255.
Default: 50
Result Codes: OK if the <interval> is 0-255.
ERROR if the <interval> parameter entered is out of range or if not in voice mode.
Reports: +VRA? Displays current or selected values.
+VLS=? Displays a list of the supported values.

+VRN Ringback Never Appeared Timer

Description: Sets the length of time that the modem will wait for ringback. If the modem does not

detect a ringback within the time period <interval>, the modem assumes that the
remote device has going off-hook., and returns the OK result code. The modem only
used this command in call origination transactions. A +VRN setting greater than the
S-Register S7 setting means that only the S7 timer is in effect. Entering +VRA=0

forces the modem to return the OK result code immediately after dialing.
Syntax: AT+VRN=<interval>
Values: <interval> A decimal number specifying the time period, in units of 1.0 seconds that

the modem will wait for ringback during a call origination. A value of 0
forces the modem to report the OK result code immediately after dialing.

The range is 1 to 25 seconds for <interval>=1 to 25.
Values: 0–10 (in 1.0 second increments)
Default: 10 (10 seconds)
Result Codes: OK if <interval> = 0-25.
ERROR if the <interval> parameter entered is out of range or the modem is not in

voice mode.
Reports: +VRN? Displays current or selected values.
+VLN=? Displays a list of the supported values.

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Chapter 4 – Voice Commands

+VSD Silence Detection Sensitivity

Description: Sets the silence detection sensitivity and the required period of silence before the

modem reports silence detected at the end of a voice receive, either with the

Presumed End of Message (Quiet) or Presumed Hang Up (Silence) event reports.

The table below outlines the possible combinations of the +VSD and +VSM

commands using the <sds> parameter. An <sdi> parameter value of 0 means that

long-term silence detection is disabled. (Note that long-term silence detection refers

to the use of this function to detect the end of a voice receive (i.e., the user stops

talking).
The parameter <sds> is used by the PC to select greater amounts of modem silence

detection activity; larger values imply that the PC wants the modem to treat noisier

conditions as silence. The value entered for <sds> has no actual unit of measure.

The modem may limit silence detection sensitivity to a more narrow range (e.g., from

120 to 136). A setting of 0 has no meaning.
The parameter <sdi> sets the required period of silence before the modem can report

silence detected either with the Presumed End of Message (Quiet) or Presum ed

Hang Up (Silence) event reports. A value of 0 disables modem silence detection, in

which case the modem will not report the Presumed End of Message (Quiet) or

Presumed Hang Up (Silence) event reports.
Syntax: AT+VSD=<sds>,<sdi>

Values: <sds> A decimal number corresponding to the selected parameter:
0 Use +VSM silence compression setting and algorithm for long-term

silence detection if +VSM is in use
OR
Use default long-term setting silence detection level and algorithm if

+VSM is not in use.
127 Sets less aggressive long-term silence detection independent of

presence or use of silence compression.
128 Sets nominal long-term silence detection independent of presence or

use of silence compression.
129 Sets more aggressive long-term detection independent of presence or

use of silence compression.
<sdi> A decimal number specifying the required period of silence in units of 0.1

seconds, before the modem can report silence detected at the end of a

voice receive either with the Presumed End of Message (QUIT) or

Presumed Hang up (SILENCE) event reports. A value of 0 disables the

modem silence detection. The range is 0.1 to 25.5 seconds for <sdi>=1

to 255.
Result Codes: OK if values are valid.
ERROR if one or more of the following apply: 1) the <sds> or <sdi> parameter

entered is out of range, or 2) either of the two parameters is missing from the
command string. If an error occurs, modem retains the previous <sds> and <sdi>

parameter values.
Reports: +VSD? Displays current or selected values.
+VSD=? Displays a list of the supported values.

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Chapter 4 – Voice Commands

+VSM Select Voice Compression Method

Description: Sets the modem to a specified voice compression method, silence compression

sensitivity, and voice sampling rate. The modem can maintain a different event

detection capability for each compression method. For example, you may want to

record your welcome message with the lowest amount of silence removal, with the

goal of reducing distortion. For other messages you may want a more assertive

silence removal, to limit disk space used for recording purposes.
Syntax: AT+VSM=<cml>,<vsr>,<scs>,<sel>

Values: <cml> A decimal number identifying the compression method. The valid values are

1, 129, 130, 140, 141.

<vsr> A <range of values> containing the supported range of for voice samples per

second of the analog signal (8000).

<scs> A <range of values> containing the supported range of sensitivity settings for

voice receives.
Has different meanings in voice transmit and voice receive modes.
In receive, the PC uses <scs> to select greater amounts of compression

activity; larger <scs> values mean that the PC wants the modem to treat

noisier conditions as silence. There is no unit of measure for this parameter;

it merely represents a number in a range.
In voice transmit mode, the PC signals the modem that the data stream was

recorded with silence compression by selecting a non-zero value from within

the valid range (the same value as receive).

Unpredictable results can occur if you 1) enable silence compression for

transmitting a voice data stream that was not recorded with silence

compression enabled, or 2) you disable silence compression for transmitting

a voice data stream that was recorded with silence compression enabled
<sel> A <range of values> containing the supported range of expansion values for

voice transmit. This parameter represents the minimum amount of silence

that the modem will expand a period of silence that was previously deleted

with a non-zero <sel> parameter. A setting of <sel>=0 means the modem

will not modify the silence expansion. The valid range of values is ____ -

____ in 0.1second increments. The modem ignores the <sel> parameter if

the <scs> parameter is 0 (silence compression disabled).
You can modify the silence expansion with the <sel> parameter. The range

of valid values is 0–255. The modem may limit silence compression

sensitivity to a narrower range (e.g., 120–128). A setting of <scs>=0

disables silence compression.

Result Codes: OK if the modem accepts the command.
ERROR if one or more of the following apply: 1) the any parameter entered is out of

range, or 2) any of the four parameters are missing from the command string. If an
error occurs, the modem retains the previous <sds> and <sdi> parameter values.

Reports: +VSM? Displays current or selected values.
Reports <cml>,<vsr>,<sds>,<sel>
Example: 1,8000,0,0. This is the default.
+VSM=? The +VSM=? command reports several compression method identifiers

in one of two ways: either 1) a compression method (for PCM coding)
from the table below, or 2) a co-operative identifier (non-PCM coding)

used with other manufacturer's equipment.
Reports the following:
<cml> See above
<cmid> An alphanumeric string describing the compression method
(UNSIGNED PCM, IMA ADPCM, 2-Bit ADPCM, or 4-Bit

ADPCM)

Continued on next page.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 51

Chapter 4 – Voice Commands

<bps> A decimal number defining the average number of bits in the

compressed sample not including silence compression (2, 4,
or 8)

<tm> A decimal number (0) reporting the time interval in units of

0.1 seconds between timing marks. 0 reports timing marks

are not supported.
<vsr> See above. A report of 0 indicates not supported.
<scs> See above. A report of 0 indicates not supported.

<sel> See above. A report of 0 indicates not supported.
Example: The following shows an inquiry about the modem support of
compression and other data. In this example, the modem reports that it
supports two compression methods.

AT+VSM=?
128,"SIGNED PCM",12,0,(7200-8000,11025),(127-129),(0-50)
132,"ADPCM/AQ",2,40,(7200),(128),(0-50)

+VTD=<dur> Beep Tone Duration Timer (DTMF/Tone Generation Duration)

Description: Sets the default DTMF/tone generation duration used with the +VTS command. This

command does not affect the ATD command settings. The <dur> parameter range is
given by the +VTD=? command, in units of 0.01 seconds. A setting of +VTD=0

specifies a manufacturer-specific time interval.
Syntax: AT+VTD=<dur> .
Values: <dur> A decimal number specifying the default DTMF/tone generation duration in

units of 0.01 seconds.

A value of 0 specifies the value entered by the S11 parameter (50 to 255

ms). the range is 0.01 to 2.55 seconds for <dur> 1 to 255. Default = 100.
Result Codes: OK if <dur> = 0-255.
ERROR if the parameter is out of range or if not in Voice mode.
Reports: +VTD? Displays current or selected values.
+VTD=? Displays a list of the supported values.

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Chapter 4 – Voice Commands

+VDR Distinctive Ring (Ring Cadence Reporting)

Description: Enables or disables reporting of the ring cadence information and controls the timing

of the Ring event code report if ring cadence reporting is enabled.

This report format is one line per silence period, and one line per ring period. The

length of the silence period is in the form DROF=<number in units of 0.1
seconds><CR><LF>, and the length of the ring in the form DRON=<number in units
of 0.1 seconds>. The <LR> character is optional. The modem may produce a Ring
event code after the DRON message if enabled by the <report> parameter. The
<report> parameter should be set to a value larger than the expected off-times within
a single pattern so that the Ring event reports are issued only during the off-times
between the complex patterns.

Syntax: AT+VDR=<enable>,<report>
Values: <enable> A decimal nu m ber corresponding to the selected option:
0 The modem will not generate ring cadence reports. Other call

progress event codes (including Ring) are reported as normal.

1 The modem will report ring cadence information as specified for the

<report> subparameter. Default.

<report> A decimal number specifying ring cad ence information report when

enabled by the <enable> subparameter.

0 The modem will produce only DROF and DRON messages. The

modem will not produce a RING event codes. The modem will
report other call progress event codes as normal.

Other The modem will produce only DROF and DRON messages.

The modem will produce a RING event code after <report>/10
seconds after the falling edge of the ring pulse (i.e., after the
DRON report).. The modem will report other call progress

event codes as normal.
Example: The lines below shows a cadence with an off time of 4.0 seconds, an on
time of 0.8 seconds, an off time of 0.4 seconds, and an on time of 0.8 seconds. The
RING result code is displayed 0.5 seconds after the last DRON message. The
command to enable this sample sequence is +VDR-1,5 , as shown below:

<DLE><X>
DROF=40
DRON=8
DROF=4
DRON=8
RING
<DLE><.>
<DLE><X>
DROF=40
DRON=8
DROF=4
DRON=8
RING
<DLE><.>

Reports: +VDR? Displays current or selected values.
+VDR=? Displays a list of the supported values.
Result Codes: OK if the modem accepts the command
ERROR if the parameter is out of range or not in voice mode.

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Chapter 4 – Voice Commands

+VEM Event Reporting and Masking

Description: The +VEM= command can be used to disable an event report, regardless of the

modem's state, or of the modem's analog signal source or destination's configuration.
The <mask> parameter is a bit field where bit 0 is the most significant bit of an eight­digit hex number. The PC setting of a bit enables event reporting for that event. Bit 0
in the bit field corresponds to Event number 0 (Caller ID). This mask effects the
reporting of the specified event in all modes (Fax, On-line data, AT Command and
Voice modes). Events cannot be masked by modes; however, the PC can change
the mask each time it changes modes. The modem-detectable events depend on the
compression method selected by the +VSM command. The +VEM command may
effect the reporting capabilities of other +V commands. The detection of an event
may not be possible at all times and for all compression methods. Use the +VLS=?
command to ask which times and for which compression methods (as well as for
which analog source/destination selections) events can be detected and reported
when not disabled by the +VEM command.

Syntax: AT+VEM=<mask>
Values: bits 0–32 on (i.e., FFFFFFFF8)
Example: In the lines below, only the RING and the DTMF event detection reporting:

AT+VEM=18000000

OK
Reports: +VEM? Displays current or selected values.
+VEM=? The +VEM=? command returns four lines of modem event

reporting/masking capability information, followed by the OK result code.
The first line indicates the Service Level supported by the modem
(though the modem may support more than the capabilities displayed).
The next three lines report the capability of the Voice Transmit mode,
Voice Receive mode, and the Voice Command mode, respectively. Each
line is a hex value that is the bit-wise OR function across all of the
supported compression methods and across all analog
source/destination hardware configurations (i.e., all +VLS settings) for
the specified mode. Note that the displayed hex values are not
connected to the <mask> parameter in the +VEM and +VEM?
commands.

Result Codes: OK if the modem accepts this command
ERROR if the bit field contains illegal characters.

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 54

Chapter 4 – Voice Commands

Interface Configuration Commands

The commands in this section are used to define the interface between the PC and the modem.

+VBT Set Modem Flow Control Assert and Deassert Points

Description: The +VBT= command is used to set the flow control assert and deassert points

inside the modem's internal transmit buffer. As data is sent from the PC to the

modem and is stored in the modem's buffer, when the number of octets in the buffer

equals the <assert> value, the modem asserts flow control to the PC (e.g., turns off

CTS circuits, or sends an XOFF character). As the modem removes data from the

buffer and processes the data, when the number of octets in the buffer equals the

<deassert> value, the modem de-asserts flow control (e.g., turns on CTS circuits, or

sends an XON character). The modem may inform the PC (using the +VBT=?

command) that the PC does not permit the modifying of the flow control assert and

deassert points by returning a single value, not in the range of values, for each

control point.
The +VBT= command controls the amount of "skid" in the modem's voice buffer,

where "skid" is the amount of octets that the modem could accept before losing data

after the modem asserts an off flow control signal to the PC.
You can use the +VBT= command to balance performance versus robustness. For

example, if the PC knows there are only 16450 UARTs present, a small "skid" is

probably sufficient. If there are 16550 UARTs present, a larger "skid" is probably

required.
Syntax: AT+VBT=<deassert>,<assert>
Values: <assert> and <deassert> are buffer offsets from the start of the buffer. The buffer's

first position is 0. The offset units are octets.
Reports: +VBT? Displays current or selected values.

+VBT=? Displays the possible <assert> and <deassert> values set by the +VBT=

command, followed by the OK result code.

Example: In the lines below, the +VBT=? command is used to ask about the modem's flow

control and buffer size ranges. The modem reports the deassert point is adjustable

between 20 and 100 octets, the assert point is adjustable between 150 and 180

octets, and the transmit buffer size is 200 octets.

AT+VBT=?
(20-100) , (150-180) , (200)

OK
Result Codes: OK if the modem accepts the command
ERROR if either the <assert> or <deassert> parameter is greater than the buffer size,

or if the <de-assert> parameter is greater than or equal to the <assert> value.

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Chapter 4 – Voice Commands

+VPP Enable or Disable Voice Mode Packet Protocol

Description: The +VPP= command enables and disables the Packet protocol for Voice mode

operation, and handles the new unsolicited Voice mode result codes. The Packet
protocol is used to detect lost octets on the modem-to-PC serial link, and to recover
the lost octets by requesting retransmission. The Packet protocol assumes that the
data corruption is not a problem on the communications link, the last octet sent will
never be lost due to data overrun (i.e., that the newer octets always overwrite
previous octets in the communications input buffer, a common UART design feature).

Several PC processes can cause serial input channel neglect for longer than the
Protocol time between asynchronous characters (typically less than 521
microseconds), and data loss can occur. If a character is lost in the received data,
the playback of the voice data may be impaired or lost. If a character is lost in the
final result code, the connection may fail. The Packet protocol permits recovery from

such data loss.
Syntax: AT+VPP=<enable>
Values: 0, 1; (2–255 reserved for future standards)
Result Codes: OK if the modem accepts the command.
ERROR if the <enable> value is out of range.

+VPR Select DTE/DCE Interface Rate (Turn Off Autobaud)

Description: The +VPR= command causes the modem to select between various fixed modem-to-

PC interface rates and autobauding. The selected fixed interface rate stays in effect

until the modem selects another interface rate or autobauding, or until the modem

returns to autobauding on the expiration of the Inactivity Timer. The newly selected

rate takes effect after the modem returns the OK result code.
Syntax: AT+VPR=<rate>
Values: +VPR=0 select autobauding
+VPR=1 select 2400 bps
+VPR=2 select 4800 bps
+VPR=3 select 7200 bps
+VPR=4 select 9600 bps
+VPR=5 select 12000 bps
+VPR=6 select 14400 bps
+VPR=7 select 16800 bps
+VPR=8 select 19200 bps

If the modem claims support for autobauding (+VPR=0), it means that the modem

can accept AT commands at 2400 bps at all times while in Voice command mode

and with +VPR=0.
Result Codes: OK if the modem accepts the command.
ERROR if the <rate> value is out of range.

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Chapter 4 – Voice Commands

Flow Control

XON/XOFF flow control is used by the modem to match the PC-to-modem data rate to the line-signaling
rate, as well as to the requirements of analog conversion of the voice signals and voice data.
In-band, uni-directional XON/XOFF flow control is mandatory. RTS/CTS (V.24 circuits 106 and 133) flow
control is optional per the IS-101 standard.

Voice Mode Result Codes

In Voice mode, the modem can detect and report DTMF, detect call progress tone and cadence events,
evaluate voice quality, and can monitor Telco-related activities. Events can be reported as a single
character (Simple or "Terse" reporting), a full-text message (Message or "Verbose" reporting), or as a
repeating pattern (Pattern reporting).

Terse

Verbose

0 Caller ID Report
1 DID Report
2 Distinctive Ringing
3 RING
4 DTMF Received
5 Receive Buffer Overrun
6 Facsimile Calling (e.g., 1100 Hz)
7 Data Calling (e.g., 1300 Hz)
8 Local Phone On/Off Hook
9 Presumed Hang Up (SILENCE) Time-out
10 Presumed End of Message (QUIET) Time-out
11 SIT Tone (CO Standard Information Tones, sent to pay phones)
12 Bong Tone (Calling Card Tone)
13 Loop Current Interruption
14 Loop Current Polarity Reversal
15* Call Waiting Beep/Interrupt*
16* Distinctive Call Waiting*
17* TDD Detected (e.g., 1400/1800 Hz)*
18 Ring Back/Remote Ring
19 BUSY
20 DIALTONE
21 Reorder/Fast Busy
22 V.21 Channel 2 7E Flags
23 Transmit Buffer Under Run
24 Extension Phone On/Off Hook
25 Facsimile or Data Answer (e.g., 2100 Hz)
26 Data Answer (e.g., 2225 Hz)
27 Voice Detect
28 Call Waiting Plus Caller ID
29 Stuttered Dial Tone
30 Invalid Voice Data Format
31 Lost Data Detected Event
32 Facsimile Answer
33-63 Reserved for future standard
above 63 Manufacturer specific
_____
* Further study required for final specification.
The TIA/EIA-602 CONNECT result code is disallowed in voice mode.

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Chapter 4 – Voice Commands

Unsolicited Voice Mode Result Codes

The form of the unsolicited result codes for voice mode is different from standard modem Command
mode result codes. The +V specification refers to these voice mode result codes as "event detection
reports". Event detection reports are provided in simple report format when one character is enough to
report an event, such as RING. A complex report format is used when one character is not enough to
report an event; generally, all multi-character responses. Complex event reports are in the format <tag>
<=> <data> <cr>, where <tag> is the data type, = is the ASCII = sign, <data> is a specific data instance,
and <cr> is ASCII 13 decimal.

Valid Complex Event Report Tags

Tag Description

TIME Caller ID Tag in the form TIME=HHMM, where HH is the hour (00-23) and MM is the

minute (00–59). All numbers are in ASCII and numbers less than 10 have a leading 0.

DATE The current date in the format MMDD (where MM is the month 0–12 and DD is the day

01–31). All numbers are in ASCII and numbers less than 10 have a leading 0.

NMBR The telephone number of the caller, in the format NMBR=<Number> or P or O (ASCII 4F

hex). The P indicates that the calling number information is not available since the
originating caller has requested Private service. The O indicates that the calling number

information is not available since the caller is outside of the area code.
NAME The caller's name in the format NAME=<Listing Name>.
MESG Indicates a data item not listed above in Multiple Message Format: MESG=<Data

Tag><Length of Message><Data><Checksum> in printable ASCII (to avoid confusion

with binary output).
ERRM Error Tag (used for Caller ID and other uses). Refer to the +VCID command.
DRON Distinctive Ring Cadence On time
DROF Distinctive Ring Cadence Off time
CPON Control Tone Cadence On time
CPOF Control Tone Cadence Off time
CWON Call Waiting Cadence On time
CWOF Call Waiting Cadence Off time
ASTB See Voice Mode Shielded Codes
SITT The data value for the SITT tag, in the format <SITT><=><data><cr>, where <data> can

mean:

ICNT Intercept Tone

VCCT Vacant Code Tone

REOT Reorder Tone

NCDT No Circuit Detected Tone

TON4 Fourth SIT Tone Number

TON5 Fifth SIT Tone Number

TON6 Sixth SIT Tone Number

TON7 Seventh SIT Tone Number

In the event of an unrecognized data tag, the SocketModem presents the data item information as
printable hex ASCII numbers following the MESG tag. For example:

RING

DATE=0321

TIME=1405

NMBR=5045551234

NAME=DOE JOE

MESG=060342424231

RING

RING

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Chapter 4 – Voice Commands

Voice Mode Shielded Codes

These codes can be sent in either Command mode or Data mode. The DCE may return the event
detection reports after the OK result code from the +FCLASS command. One or more simple event
detection reports may be embedded within the data portion of a complex event detection report. Table 3
describes voice mode shielded codes. The number in the first column is the ASCII equivalent (in hex).
Voice Mode Shielded Codes Detail

Shielded Code

<DLE> (10) Two contiguous <DLE><DLE> codes indicate a single <DLE> in the data
<SUB> (1A) <DLE><DLE> in the data stream.

<ETX> (3) End Data State; signifies the end of voice data. Can end with Event 9

Q (51) Data stream shielded Xon character. Used in the +VXT command to shield
S (53) Data stream shielded Xoff character. Used in the +VXT command to shield
M (4D) Data stream shielded SOH code used for the Packet Protocol.

W (57) Data stream shielded ETB code used for the Packet Protocol.
F (46) Data stream shielded ACK code used for the Packet Protocol.
U (55) Data stream shielded NAK code used for the Packet Protocol.
G (47) Data stream shielded ENQ code used for the Packet Protocol.
T (54) Timing Mark.
X (58) Packet Header for the "Complex Event Detection Report" (additional event

. (2E) Packet Terminator for the "Complex Event Detection Report" (additional
/ (2F) Start of DTMF tone shielding.

~ (7F) DTMF transitions to off.
R (52) Event Number 3 (RING). The <DLE> shielded version of the RING result

1 (31) Event Number 4 (DTMF 1).
2 (32) Event Number 4 (DTMF 2).
3 (33) Event Number 4 (DTMF 3).
4 (34) Event Number 4 (DTMF 4).
5 (35) Event Number 4 (DTMF 5).
6 (36) Event Number 4 (DTMF 6).
7 (37) Event Number 4 (DTMF 7).
8 (38) Event Number 4 (DTMF 8).
9 (39) Event Number 4 (DTMF 9).
0 (30) Event Number 4 (DTMF 0).
A (41) Event Number 4 (Extended Keypad DTMF A).
B (42) Event Number 4 (Extended Keypad DTMF B).
C (43) Event Number 4 (Extended Keypad DTMF C).
D (44) Event Number 4 (Extended Keypad DTMF D).
* (2A) Event Number 4 (Extended Keypad DTMF E).
# (23) Event Number 4 (Extended Keypad DTMF E).
o (6F) Event Number 5 (Receive Buffer Overrun).
c (63) Event Number 6 (Facsimile Calling).
e (65) Event Number 7 (Data Calling).
h (68) Event Number 8 (line current break). Local phone goes on hook.
H (48) Event Number 8 (line current detected). Local phone goes off hook.
s (73) Event Number 9 (Presumed Hang Up "
q (71) Event Number 10 (Presumed End of Message "QUIET" Timeout).
J (4A) Event Number 11 (SIT Tone).
$ (24) Event Number 12 (Bong Tone).

Hex Event Report Description

stream.

(Presumed Hang Up Timeout), Event 10 (Presumed End of Message), Event
13 (Loop Current Interruption), Event 14 (Loop Current Polarity Reversal),
Event 19 (BUSY), or Event 20 (DIALTONE).

XON characters in the full-duplex data stream and in the Packet Protocol.
XOFF characters in the full-duplex data stream and in the Packet Protocol.

data transfers to the DTE).
event data transfers to the DTE).

code.

SILENCE" Timeout).

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Chapter 4 – Voice Commands

I (6C) Event Number 13 (Loop Current Interruption). Usually indicates a remote

hang up.

L (4C) Event Number 14 (Loop Current Polarity Reversal). May indicate a hang up

or a receive, depending on CO implementation.
w (77) Event Number 15 (Call Waiting/Beep Interrupt).
t (74) Event Number 17 (TDD Detected - 1400/1800).
r (72) Event Number 18 (Ring Back).
b (62) Event Number 19 (BUSY). May be repeatedly sent.
d (64) Event Number 20 (DIALTONE). May be repeatedly sent.
K (4B) Event Number 21 (Reorder/Fast Busy).
F (46) Event Number 22 (V.21 Channel 2 7E flags).
u (75) Event Number 23 (Transmit Buffer Under run).
p (70) Event Number 24 (Line voltage increase - extension phone goes on hook).
P (50) Event Number 24 (Line voltage increase - extension phone goes off hook).
a (61) Event Number 25 (Facsimile or Data Answer.
f (66) Event Number 26 (Data Answer).
V (56) Event Number 27 (Voice Detection). A high confidence of voice.
v (76) Event Number 27 (Voice Detection). A low confidence of voice.
i (69) Event Number 29 (Stuttered Dial tone).
E (45) Event Number 30 (Invalid Voice Data Format. Voice data is incompatible

with selected Voice Compression Methods.
Y (59) Event Number 31 (Lost Data Detected Event).
m (6d) Event Number 32 (Facsimile Answer).
% (25) Event Number 63 (manufacturer specific).
& (26) Event Number 48 (manufacturer specific).
' (27) Event Number 49 (manufacturer specific).
( (28) Event Number 50 (manufacturer specific).
) (29) Event Number 51 (manufacturer specific).
all other 7-bit ASCII Reserved for future use.

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Chapter 4 – Voice Commands

DTE/DCE Interface Rates

The table below indicates the anticipated modem-to-computer interface rates for both the 7.2 bits-per­sample rate and the 8 bits-per-sample rate.

Projected DTE/DCE Interface Rates for 7.2/8K Hz Sample Rates

Bits per
Sample

0.5 4800 9600
1 9600 19200
2 19200 19200
3 38400 38400
4 38400 57600
5 57600 57600
6 57600 115200
7 115200 115200
8 115200 115200
9 115200 115200
10 115200 115200
11 115200 115200
12 115200 Fast
13 Fast Fast

Projected DTE/DCE
I/F Rate @ 7.2K Hz

Projected DTE/DCE
I/F Rate @ 8K Hz

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 61

Index

Index

1

10-Bit Mode......................................................32

11-Bit Mode......................................................32

3

32-bit Frame Check Sequence – +EFCS ........26

A

Abort timer – S7...............................................37

Adaptive Answer Result Code – %A................20

Answer command - A.........................................7

Asynchronous Communications Mode – &Q...16

Asynchronous Word Length $EB.....................32

AT Command Control – %DC..........................20

AT commands

#CBA – Callback Attempts...........................35

#CBD – Callback Delay................................35

#CBF – Callback Failed Attempts Display....35

#CBFR – Callback Failed Attempts Reset...35

#CBI – Local Callback Inactivity...................35

#CBN – Store Callback Password................35

#CBP – Callback Parity................................36

#CBR – Callback Security Reset..................36

#CBS – Callback Enable/Disable.................34

#P – Set 11-Bit Parity...................................34

#S – Enter Setup Password .........................34

#S= – Store Setup Password.......................34

$D – DTR Dialing..........................................32

$EB – Asynchronous Word Length..............32

$LB – Long Break.........................................32

$MB – Online BPS Speed............................32

$RP – Ring Priority vs. AT Command Priority

..................................................................33

$SB – Serial Port Baud Rate........................33

%%%ATMTSMODEM – Remote

Configuration Escape Sequence..............34

%A – Adaptive Answer Result Code............20

%B – View Numbers in Blacklist ..................20

%C – Data Compression Control.................20

%DC – AT Command Control ......................20

%DT – Set AT Command Mode Timer.........21

%E – Fallback and Fall Forward ..................21

%H – Set Callback Security – Direct Connect

Enable.......................................................21

%S – Command Speed Response...............21

&C – Data Carrier (DCD) Control.................14

&D – DTR Control.........................................14

&E – XON/XOFF Pacing Control..................14

&F – Load Factory Settings..........................14

&G – V.22bis Guard Tone Control ...............15

&K – Flow Control Selection.........................15

&L – Leased Line Operation.........................15

&P – Pulse Dial Make-to-Break Ratio..........15

&Q – Asynchronous Communications Mode16

&S – Data Set Ready (DSR)........................16

&T – Self Test commands............................16

&V – View Active Configuration ...................16

&W – Store Current Configuration ...............17

&Z – Store Dialing Location and Number ....17

+++AT – Escape Sequence...........................7

+A8E – V.8 and V.8bis Operation Controls..22
+A8T – Send V.8bis Signal and/or Message23
+DCS – Select V.42bis or V.44 Data

Compression.............................................23

+DR – V.44 Data Compression Reporting...24

+DS – V.42bis Data Compression...............24

+DS44 – V.44 Data Compression................25

+EB – Break Handling in Error Control........26

+EFCS – 32-bit Frame Check Sequence.....26

+ER – Error Control Report..........................26

+ES – Error Control Selection......................27

+ESA – Set Up Error Control Parameters....27

+ETBM – Call Termination Buffer

Management.............................................27

+FCLASS – Fax Class Indication.................28

+GCAP – Complete List of Capabilities

Request ....................................................28

+GCI – Country of Installation......................28

+GMI – Manufacturer Identification Request28

+GMM – Model Identification Request.........28

+GMR – Revision Request ..........................28

+IFC – DTE-DCE Local Flow Control ..........29

+ILRR – DTE-DCE Local Rate Reporting....29

+IPR= – Fixed DTE Rate .............................29

+ITF= – Transmit Flow Control Threshold...30

+MR= – Modulation Reporting Control ........30

+MS= – Modulation Selection......................30

+VCID – Caller ID Selection.........................34

+VDR= – Distinctive Ring Report.................33

A - Answer......................................................7

\A – Select Maximum MNP Block Size ........17

A/ – Repeat Last Command...........................7

AT – Attention Code.......................................7

B – Communication Standard Setting............7

\B – Transmit Break .....................................17

-C – Data Calling Tone.................................19

D – Dial...........................................................8

Definition ........................................................6

E – Echo Command.......................................9

F – Online Data Character Echo....................9

format.............................................................6

H – Hook Control............................................9

I – Request ID Info .......................................10

\K – Break Control........................................18

M – Monitor Speaker Mode..........................10

\N – Error Correction Mode..........................18

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Index

N – Modulation Handshake..........................11

O – Return Online to Data............................11

P – Pulse Dialing..........................................11

\Q – Local Flow Control Selection................19

Q – Result Codes Enable/Disable................11

Sr= – Set Register Value..............................12

\T – Inactivity Timer......................................19

T – Select Tone Dialing................................12

\V – Protocol Result Code............................19

V – Result Code Format...............................12

W – Result Code Options.............................12

X – Select Result Code & Call Monitor

Progress....................................................13

\X – XON/XOFF Pass-Through....................19

Z – Reset and Recall Stored Profile.............13

AT Commands

Enter key ........................................................7

Attention code command - AT ...........................7

Automatic Hang-Up Control – +VNH=.............44

B

Backspace character – S5...............................37

Beep Tone Duration Timer (DTMF/Tone

Generation Duration) – +VTD= ....................52

Bell 212A mode..................................................7

Break Control – \K............................................18

Break Handling in Error Control – +EB............26

C

Call Termination Buffer Management – +ETBM

......................................................................27

Callback Attempts – #CBA...............................35

Callback Delay – #CBD....................................35

Callback Enable/Disable – #CBS.....................34

Callback Failed Attempts Display – #CBF?.....35

Callback Failed Attempts Reset – #CBFR.......35

Callback Parity – #CBP....................................36

Callback Security Reset – #CBR.....................34

Caller ID Selection – +VCID.............................34

Carriage return character – S3 ........................37

Carrier loss disconnect time – S10..................37

Command mode.................................................6

Command Speed Response %S.....................21

Command string.................................................6

Communication Standard Setting – B................7

Complete List of Capabilities Request – +GCAP

......................................................................28

Count Rings – S1.............................................37

Country Code Display......................................10

Country of Installation – +GCI..........................28

D

Data buffering...................................................16

Data Calling Tone – -C.....................................19

Data Carrier Detect – &C.................................14

Data Compression Control – %C.....................20

Data mode..........................................................6

Data Set Ready Control – &S ..........................16

Diagnostic Information Display ........................10

Dial – D...............................................................8

Dial string modifiers ...........................................8

Dialing tones – S11..........................................37

Distinctive Ring (Ring Cadence Reporting) –

+VDR=..........................................................53

Distinctive Ring Report – +VDR= ....................33

Downstream Data Rate – S38........................38

DTE/DCE Interface Rate (Turn Off Autobaud) –

+VPR=..........................................................56

DTE/DCE Interface Rates................................61

DTE-DCE Local Flow Control – +IFC..............29

DTE-DCE Local Rate Reporting – +ILRR........29

DTR Control – &D............................................14

DTR Dialing – $D.............................................32

E

Echo Command – E...........................................9

Enable/Disable Voice Mode Packet Protocol –

+VPP=..........................................................56

Enter key............................................................7

Enter Setup Password – #S.............................34

Enter Voice Receive State – +VRX.................44

Error control – S36...........................................37

Error control – S48...........................................39

Error Control Report – +ER .............................26

Error Control Selection – +ES..........................27

Error Correction Mode – \N..............................18

Escape sequence ..............................................6

Escape Sequence – S2...................................37

Escape sequence +++AT ..................................7

Event Reporting and Masking – +VEM= .........54

F

Fallback and Fall Forward – %E......................21

Fallback in N command...................................11

Fax Class Indication – +FCLASS ....................28

Fax commands ..................................................6

Firmware Version Display................................10

Fixed DTE Rate – +IPR=.................................29

Flow Control.....................................................57

Flow Control Assert and Deassert Points –

+VBT=..........................................................55

Flow Control Selection – &K............................15

H

Handshake.......................................................11

Hook Control – H ...............................................9

I

Inactivity timer – S30........................................37

Inactivity Timer – \T..........................................19

Inactivity Timer – VIT=.....................................47

Initialization strings.............................................6

Initialize Voice Parameters – +VIP..................44

Interface Configuration commands

+VBT= – Flow Control Assert and Deassert

Points........................................................55

+VPP= – Enable/Disable Voice Mode Packet

Protocol.....................................................56

+VPR= – DTE/DCE Interface Rate (Turn Off

Autobaud).................................................56

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 63

Index

Interface Configuration Commands.................55

L

Leased Line Operation – &L............................15

Line feed character – S4..................................37

Load Factory Settings – &F..............................14

Local Callback Inactivity Timer – #CBI ............35

Local Flow Control Selection – \Q....................19

Long Break $LB ...............................................32

M

Manufacturer Identification Request – +GMI...28

MNP Error Correction.......................................18

Model Identification Request – +GMM.............28

Modulation Handshake – N..............................11

Modulation Reporting Control – +MR= ............30

Modulation Selection – +MS=..........................30

Monitor Speaker Mode – M..............................10

N

Number of Rings – S0......................................37

O

Online BPS Speed – $MB................................32

Online command mode......................................6

Online Data Character Echo – F........................9

P

Pause Length – S8...........................................37

Protocol Result Code – \V................................19

Pulse Dial Make-to-Break Ratio – &P..............15

Pulse Dialing – P..............................................11

R

Remote Configuration

Escape Character – S9 ................................37

Remote Configuration Escape sequence –

%%%ATMTSMODEM..................................34

Repeat Last Command – A/...............................7

Request ID Info – I...........................................10

Reset and Recall Stored Profile – Z.................13

Result Code Format – V...................................12

Result Code Options – W.................................12

Result codes ......................................................6

Result Codes....................................................40

Result Codes Enable/Disable – Q ...................11

Return Online to Data Mode – O .....................11

Revision Request – +GMR ..............................28

Ring Priority vs. AT Command Priority – $RP.33

Ringback Goes Away Timer – VRA=...............49

Ringback Never Appeared Timer – +VRN=.....49

ROM Checksum...............................................10

S

Select Analog Source/Destination – +VLS= ....48

Select Maximum MNP Block Size command – \A

......................................................................17

Select Result Code & Call Monitor Progress – X

......................................................................13

Select Tone Dialing – T ...................................12

Select V.42bis or V.44 Data Compression –

+DCS............................................................23

Select Voice Compression Method – +VSM= .51

Select Voice Mode – +FCLASS=8...................44

Self Test commands – &T ...............................16

Send V.8bis Signal and/or Message – +A8T...23

Send Voice Tones – +VTS=............................45

Serial Port Baud Rate – $SB...........................33

Set AT Command Mode Timer – %DT............21

Set Callback Security – Direct Connect Enable

%H................................................................21

Set Register Value – Sr=.................................12

Set Sleep Mode – S24.....................................37

Set the Volume for Transmitted Voice Samples

– +VGT=.......................................................46

Set Up Error Control Parameters – +ESA.......27

Silence Detection Sensitivity – +VSD=............50

sleep mode – S89............................................39

Speed

Maximum – S37 ...........................................38

S-registers

S2 – Escape Sequence................................37

S-Registers......................................................37

S0 – Sets Number of Rings..........................37

S1 – Counts Rings.......................................37

S10 – Carrier Loss Disconnect Time ...........37

S11 – Dialing Tones.....................................37

S24 – Set Sleep Mode.................................37

S28 – V.34 Modulation.................................37

S3 – Carriage Return...................................37

S30 – Inactivity Timer...................................37

S35 – V.25 Calling Tone..............................37

S36 – Error Control......................................37

S37 – Maximum Speed................................38

S38 – Downstream Data Rate .....................38

S4 – Line Feed Character............................37

S43 – Testing and Debugging......................38

S48 – Error Control......................................39

S5 – Backspace Character ..........................37

S6 – Wait Time for Dail Tone.......................37

S7 – Abort Timer..........................................37

S8 – Pause Length.......................................37

S89 – Standby..............................................39

S9 – Remote Configuration Escape Character

..................................................................37

Standby mode delay time – S89......................39

Start Voice Transmission Process – +VTX......46

Store Callback Password – #CBN...................35

Store Current Configuration – &W...................17

Store Dialing Location and Number – &Z........17

Store Setup Password – #S=...........................34

T

Testing and Debugging – S43.........................38

Transmit Break – \B.........................................17

Transmit Flow Control Threshold – +ITF=.......30

U

Unsolicited Voice Mode Result Codes ............58

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 64

Index

V

V.22 mode..........................................................7

V.22bis Guard Tone Control – &G...................15

V.25 calling tone – S35....................................37

V.34 modulation – S28.....................................37

V.42 Error Correction.......................................18

V.42bis Data Compression – +DS...................24

V.44 Data Compression – +DS44....................25

V.44 Data Compression Reporting – +DR.......24

V.8 and V.8bis Operation Controls – +A8E .....22

View Active Configuration – &V .......................16

View Numbers in Blacklist – %B......................20

Voice commands

+FCLASS= – Select Voice Mode.................44

+VDR= – Distinctive Ring (Ring Cadence

Reporting ..................................................53

+VEM= – Event Reporting and Masking......54

+VGR= – Voice Gain for Received Voice

Samples....................................................46

+VGT= – Set Volume for Transmitted Voice

Samples....................................................46

+VIP – Initialize Voice Parameters...............44

+VIT= – Set DTE/DCE Inactivity Timer........47

+VLS= – Select Analog Source/Destination 48

+VNH= – Automatic Hang-up Control..........44

+VRA= – Ringback Goes Away Timer.........49

+VRN= – Ringback Never Appeared Timer.49

+VRX – Enter Voice Receive State..............44

+VSD= – Set Silence Detection Sensitivity..50

+VSM= – Voice Compression Method.........51

+VTD= – Beep Tone Duration Timer

(DTMF/Tone Generation Duration)...........52

+VTS= – Send Voice Tones.........................45

+VTX – Start Voice Transmission Process..46

Voice Commands.............................................42

Voice Gain for Received Voice Samples –

+VGR= .........................................................46

Voice Mode Result Codes...............................57

Voice Mode Shielded Codes ...........................59

W

Wait time for dial tone – S6..............................37

X

XON/XOFF Pacing Control – &E.....................14

XON/XOFF Pass-Through – \X .......................19

Multi-Tech Systems, Inc. AT Commands for the MultiModem & SocketModem MT9234 Series (S000434D) 65