Multitech SocketModem MT5600SMI User manual

SocketModem
SocketModemMT5600SMI
SocketModemMT5656SMI
AT Commands
Fax Commands
Voice Commands
Reference Guide

Copyright and Technical Support
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 2
SocketModemReference Guide
MT5600SMI and MT5656SMI
S000306C, Rev. C
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 © 2002-2006, by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representations or warranties 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 09/04/03 First release.
B06/04/04 Created a separate Universal Socket Hardware guide and a separate AT
Command Reference Guide.
C 01/12/06 Added a chapter that covers setting country/regional codes. Clarified the
default for Command B and S-Register S27 (bit 6).
Patents
This device covered by one or more of the following patents: 6,219,708; 6,031,867; 6,012,113; 6,009,082;
5,905,794; 5,864,560; 5,815,567; 5,815,503; 5,812,534; 5,809,068; 5,790,532; 5,764,628; 5,764,627;
5,754,589; 5,724,356; 5,673,268; 5,673,257; 5,644,594; 5,628,030; 5,619,508; 5,617,423; 5,600,649;
5,592,586; 5,577,041; 5,574,725; 5,559,793; 5,546,448; 5,546,395; 5,535,204; 5,500,859; 5,471,470;
5,463,616; 5,453,986; 5,452,289; 5,450,425; 5,355,365; 5,309,562; 5,301,274
Other Patents Pending.
Trademarks
Registered Trademarks of Multi-Tech Systems, Inc. are SocketModem and the Multi-Tech logo.
Microsoft and Windows are registered trademarks or trademarks of Microsoft Corporation in the United
States and/or other countries. All other trademarks are owned by their respective companies.
World Headquarters
Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112
Phone: [phone] or 800-328-9717
Fax: [phone]
Technical Support
Country By Email By Phone
France: [e-mail] (33) 1-64 61 09 81
India: [e-mail] 91 (124) 6340778
U.K.: [email protected]k (44) 118 959 7774
U.S. and Canada: [e-mail] [phone]
Rest of the World: oemsale[email protected] [phone]
Internet Address: http://www.multitech.com

Table of Contents
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 3
Contents
Chapter 1 – AT Commands, S-Registers and Result Codes....................................................................4
Introduction................................................................................................................................................ 4
Escape Code Sequence – +++ ................................................................................................................. 4
Data Commands........................................................................................................................................ 5
Generic Modem Control Commands ..................................................................................................... 5
DTE-Modem Interface Commands.......................................................................................................... 11
Call Control Commands .......................................................................................................................... 16
Modulation Control Commands............................................................................................................... 26
Error Control Commands......................................................................................................................... 30
Data Compression Commands ............................................................................................................... 35
V.8/V.8bis Commands............................................................................................................................. 38
Diagnostic Commands ............................................................................................................................ 40
Example Modem Response and Usage ..............................................................................................44
Compatibility Commands......................................................................................................................... 45
Fast Connect Commands........................................................................................................................ 46
V.92 +P and –Q Commands ................................................................................................................... 47
S-Registers.............................................................................................................................................. 51
Result Codes ........................................................................................................................................... 59
Chapter 2 – Fax Class 1 Commands.........................................................................................................62
Fax I/O Processing .................................................................................................................................. 62
DTE-to-Modem Transmit Data Stream ................................................................................................ 62
Modem-to-DTE Receive Data Stream.................................................................................................62
Fax Mode Selection ............................................................................................................................. 63
Fax Origination.....................................................................................................................................63
Fax Answering ..................................................................................................................................... 63
Fax Control Transmission ....................................................................................................................63
Fax Control Reception ......................................................................................................................... 64
Fax Data Transmission ........................................................................................................................ 65
Fax Data Reception ............................................................................................................................. 65
Commands and Parameters ................................................................................................................... 66
Mode Entry Commands .......................................................................................................................66
Mode Commands................................................................................................................................. 66
Service Class 1 Commands .................................................................................................................... 70
Examples................................................................................................................................................. 74
Chapter 3 – Fax Class 2 Commands.........................................................................................................76
Command and Syntax Guidelines........................................................................................................... 77
Mode Entry Commands .......................................................................................................................77
DTE Commands .................................................................................................................................. 77
Serial Port Speed and Flow Control ....................................................................................................78
Auto Answer.........................................................................................................................................79
Identification of T.30 Options ............................................................................................................... 79
Session Status Reporting .................................................................................................................... 79
Procedure Interrupt Negotiation........................................................................................................... 79
Service Class 2 Identification and Selection ........................................................................................... 80
Service Class 2 Action Commands ......................................................................................................... 81
Service Class 2 DCE Responses............................................................................................................ 88
Service Class 2 Parameters .................................................................................................................... 91
Example Sessions ................................................................................................................................... 95
Chapter 4 – Voice Commands...................................................................................................................97
Voice Commands Overview .................................................................................................................... 97
<DLE> Shielded Event Codes Sent to the DTE .................................................................................. 98
<DLE> Shielded Codes Sent to the Modem (DCE)............................................................................. 99
Voice Configuration Commands............................................................................................................ 100
Basic Voice Commands ........................................................................................................................ 101
Chapter 5 – Setting Country or Regional Codes...................................................................................112
Index...........................................................................................................................................................113

Chapter 1 – AT Commands, S-Registers and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 4
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 mode from data mode, you must issue an escape sequence
(+++) followed immediately by the AT characters and the command, e.g., +++ 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 98 and NT 4.0, 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 autoanswer on or off.
The format for entering an AT command is ATXn, where Xis the command, and nis 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” (See below).
You must press ENTER (depending on the terminal program it could be some other key) to send 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 “Result Codes” at the end of
this chapter for a table of valid result codes.
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.
Escape Code Sequence – +++
When the modem has established a connection and has entered online data mode, it is possible to break
into the data transmission in order to issue further commands to the modem in an online command mode.
This is achieved by the DTE sending to the modem a sequence of three ASCII characters specified by S-
Register S2. The default character is '+'. The maximum time allowed between receipt of the last character
of the three-escape character sequence from the DTE and sending of the OK result code to the DTE is
controlled by the S12 register.

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 5
Data Commands
The modem will respond to the commands detailed below. Parameters applicable to each command are
listed with the command description.
Generic Modem Control Commands
Command: Z Soft Reset and Restore Profile
Description: Causes the modem to perform a soft reset and restore (recall) the
configuration profile. If no value is specified, zero is assumed.
Default: None
Values: Number corresponding to the selected profile:
Z0 Soft reset and restore stored profile 0.
Z1 Soft reset and restores stored profile 1.
Result Codes: OK
Otherwise ERROR
Command: +FCLASS Select Active Service Class
Description: Selects the active service class (mode).
Default: 0
Defined Values: +FCLASS=0 Select Data Mode (Default).
+FCLASS=1 Select Facsimile Class 1 Mode.
+FCLASS=1.0 Select Facsimile Class 1.0 Mode.
+FCLASS =2 Fax Service Class 2
+FCLASS=2.0 Fax Service Class 2.0
+FCLASS=2.1 Fax Service Class 2.1
+FCLASS=8 Select Voice Mode.
+FCLASS=10 Reserved.
Note: Fax Class 2 and Voice Mode apply to MT5656SMI only
Result Codes: OK
Otherwise ERROR
Report Commands: +FCLASS? Reports Current or Selected Values
+FCLASS=? Reports Range of Parameters
Command: +VCID Caller ID (CID)
Description: Controls the reporting and presentation of data associated with the Caller
ID services in the Incoming Call Line ID (ICLID) data format for the next
call. (U.S. only)
Default: 0
Defined Values: +VCID0 Disable Caller ID reporting.
+VCID1 Enables Caller ID with formatted presentation to the DTE. The
modem presents the data items in a <Tag><Value> pair
format. The expected pairs are date, time, name, and caller
code (telephone number).
+VCID2 Enables Caller ID with unformatted presentation to the DTE.
Report Commands: +VCID? Reports the Mode
+VCID=? Reports Range of Parameters

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 6
Command: +VRID Report Retrieved Caller ID (CID)
Description: Reports the data associated with the Caller ID services in the Incoming
Caller Line (ICLID) data format for the last received call. U.S. only
Default: None
Defined Values: +VRID0 Reports Caller ID with formatted presentation to the DTE. The
modem presents the data items in a <Tag><Value> pair
format. The expected pairs are date, time, name, and caller
code (telephone number).
+VRID1 Reports Caller ID with unformatted presentation to the DTE.
Report Commands: +VRID? Reports the Mode
Command: \N Operating Mode - Error Correction
Description: Controls the preferred error-correcting mode to be negotiated in a
subsequent data connection. This command is affected by the OEM
firmware configuration.
Default: 5
Defined Values: \N0 Selects normal speed buffered mode (disables error-correction
mode). (Forces &Q6.)
\N1 Serial interface selected: Selects direct mode and is equivalent to
&M0, Q0 mode of operation. (Forces &Q0.) Parallel interface
selected: Same as \N0.
\N2 Selects reliable (error-correction) mode. The modem will first attempt
a LAPM connection and then an MNP connection. Failure to make a
reliable connection results in the modem hanging up. (Forces &Q5,
S36=4, and S48=7.)
\N3 Selects auto-reliable mode. This operates the same as \N2 except
failure to make a reliable connection results in the modem falling
back to the speed buffered normal mode. (Forces &Q5, S36=7, and
S48=7.)
\N4 Selects LAPM error-correction mode. Failure to make an LAPM
error-correction connection results in the modem hanging up.
(Forces &Q5 and S48=0.) Note: The -K1 command can override the
\N4 command.
\N5 Selects MNP error-correction mode. Failure to make an MNP error-
correction connection results in the modem hanging up. (Forces
&Q5, S36=4, and S48=128.)
Result Codes: OK
Otherwise ERROR
Command I Identification
Description: Causes the modem to reports the requested result according to the
command parameter.
Default: None
Defined Values: I0 Reports product code (e.g., 56000).
I1 Reports the least significant byte of the stored checksum (e.g.,
12AB).
I2 Checks ROM and verifies the checksum. Reports OK or ERROR.
I3 Reports ROM Code Revision-Modulation (e.g., 2109-V90).
I4 Reports OEM defined identifier string in binary format (default) or
ASCII formats. (e.g.: a007040284C6002F bC60000000
r1005111151012000 3000111170000000).
I5 Reports Country Code parameter (see +GCI).
I6 Reports modem data pump model and internal code revision.
Result Codes: OK
Otherwise ERROR

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 7
Command: +GMI Request Manufacturer Identification
Description: Causes the modem to report the modem product manufacturer.
Typical Response: +GMI: Multi-Tech
OK
Command +GMM Request Model Identification
Description: Causes the modem to report the modem product.
Typical Response: +GMM: V92
Command: +GMR Request Revision Identification
Description: Causes the modem to report the modem version, revision level, or date.
This is the same as the I3 command.
Typical Response: +GMR: P2109-V90
OK
Command: +GCAP Request Complete Capabilities List
Description: This extended-format command causes the modem to transmit one or
more lines of information text listing additional capabilities command
+<name>s, which is intended to permit the user to identify the overall
capabilities of the modem. In particular, if the modem implements a
particular modem control standard that uses Extended Syntax Commands,
and if that modem control standard includes command(s) that indicate
general capabilities, the +<names>(s) of those commands will be reported
to the modem in response to a +GCAP command.
Example Responses: +GCAP: +FCLASS, +MS, +ES, +DS, for a data modem that supports all
capabilities listed. Where:
+MS +M commands (Modulation Control: +MS and +MR commands)
+ES +E commands (Error Control: +ES, +EB, +ER, +EFCS, +ETBM)
+DS +D commands (Data Compression: +DS and +DR). Manual
Command: +GCI Country/Region of Installation
Description: This extended syntax command selects and indicates the country or region
of installation for the modem. This parameter selects the settings for any
operational parameters that need to be adjusted for national regulations or
telephone networks. The chapter Setting Country Codes for more
information.
Default: If the modem is specified for use in only one country, that country code is
the default. Otherwise, the default is defined by the OEM. Factory default is
B5 (United States).
Report Commands: +GCI? Reports the current country code.
+GCI=? Displays the list of available country codes.
Command: &F Restore Factory Configuration (Profile)
Description: The modem loads the factory default configuration (profile). The factory
defaults are identified for each command and in the S-Parameter
descriptions. A configuration (profile) consists of a subset of S-Parameters.
Default: None
Values: &F0 Restore factory configuration 0.
&F1 Restore factory configuration 1.
Result Codes: OK
ERROR if the modem is connected.

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 8
Command: &T Local Analog Loopback Test
Description: The modem will perform the local analog loopback test if &T1 is selected.
The test can be run only when in an asynchronous operation in non-error-
correction mode (normal), e.g., AT&Q6. To terminate the test in progress,
the escape sequence must be entered first.
Default: None
Defined Values: &T0 Terminates test in progress. Clears S16.
&T1 Initiates local analog loopback, V.54 Loop 3. Sets S16 bit 0. If a
connection exists when this command is issued, the modem hangs
up. The CONNECT XXXX message is displayed upon the start of
the test.
Command: &Y Designate a Default Reset Profile
Description: Selects which user profile will be used after a hard reset.
Default: None
Defined Values: &Y0 The modem will use profile 0.
&Y1 The modem will use profile 1.
Result Codes: OK
ERROR if <value> > is1 or if NVRAM is not installed or is not operational.
Command: &W Store Current Configuration
Description: Saves the current (active) configuration (profile), including S-Parameters,
in one of the two user profiles in NVRAM as denoted by the parameter
value. This command will yield an ERROR message if the NVRAM is not
installed or is not operational as detected by the NVRAM test.
The current configuration is comprised of a list of storable parameters
illustrated in the &V command. These settings are restored to the active
configuration upon receiving a Zcommand or at power up (see &Y
command).
Default: 0
Defined Values: &W0 Store the current configuration as profile 0.
&W1 Store the current configuration as profile 1.
Result Codes: OK
Otherwise ERROR
Command &Zn=xStore Telephone Number
Description: The modem can store up to four telephone numbers and each telephone
number dial string can contain up to 31 digits. (Requires 256-byte NVRAM
installed.)
Default: None
Defined Values: <string> Dial string from 0 to 31 characters.
Result Codes: OK For <value> =3, and <string> =31 digits.
ERROR If <value> > 3, <string> > 31 digits, or if NVRAM is not installed or
is not operational.
Command %7 Plug and Play Serial Number
Description: Sets and stores eight serial numbers in hex format used for serial Plug and
Play and for ISA Plug and Play which use the Conexant 11596 Plug and
Play device. Applicable to Desktop configuration only.
Example: %7<8 hex numbers><same 8 hex numbers>
Result Codes: OK <8 hex numbers><same 8 hex numbers>
Otherwise ERROR
Report Command: AT"? Reports the stored serial number, issue.

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 9
Command %8 Plug and Play Vendor ID and Product Number
Description: Sets and stores Vendor ID and product number for serial Plug and Play
and for ISA Plug and Play which use the Conexant 11596 Plug and Play
device. Applicable to Desktop configuration only.
Default: None
Example: %8<3 ASCII characters><4 hex numbers><same 3 ASCII
characters><same 4 hex numbers><cr>
Result Codes: OK <3 ASCII characters><4 hex numbers><same 3 ASCII
characters><same 4 hex numbers>
Otherwise ERROR
Command ** Load Flash Memory
Description: The linear flash memory uploader allows flash memory connected to the
modem external memory bus to be upgraded with revised modem
firmware. This process transfers (uploads) the upgraded modem firmware
(data) from the host computer to the modem which transfers the data to the
flash memory device. The linear flash memory downloader allows the flash
memory connected to the modem external memory bus to read and saved.
This process transfers (downloads) the current modem firmware (data) to
the host computer. Uploading new firmware to the flash memory or
downloading existing firmware from the flash memory device is a two-step
process.
1. When the AT** command is issued, the modem firmware boot loader is
invoked and the user will first load a flash load module (FLM) into the
modem's RAM. If the user wishes to upload new firmware to the
modem, he should load the uploader FLM. If the user wishes to
download existing firmware from the modem, he should load the
downloader FLM. In either case, the data transfer is done via an ASCII
transfer. The FLM contains the programming algorithm for the flash
memory device being programmed and any messages that may be sent
during the load process.
2. If the user wishes to upload new firmware to the modem, then he will
then load the new modem firmware, which the uploader FLM will then
program into the flash memory device. This transfer is done via
XMODEM transfer. If the user wishes to download existing firmware
from the modem, then he will set up the host PC for XMODEM receive
and the downloader FLM will begin to send the existing firmware from
the flash memory to the host PC.
Procedure
1. Install in the modem a flash memory programmed with the modem
firmware or a blank flash memory.
2. Put the uploader FLM and downloader FLM files and the new modem
firmware file (e.g., XmUL003.s37, XmDL003.s37, and 206s4712.S37)
in an appropriate directory on the computer's hard disk.
3. Configure the communications application program for a DTE rate of
between 9600 bps and 115200 bps and RTS/CTS flow control.
4. Check the modem for response by typing AT.
5. Initiate the download process using the AT** command. The
"Download flash code…" message appears upon issuing the AT**
command.
6. Perform an ASCII transfer of the FLM file (e.g., XmUL003.s37 for
uploading new firmware to the modem or XmDL003.s37 for
downloading existing firmware from the modem) from the host
computer to the modem RAM using an industry standard
communications software or an equivalent process (ensure that all
ASCII translation or pacing is turned off).

Chapter 1 – AT Commands, S-Registers and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 10
7. After the FLM has been loaded, if uploading new firmware to the
modem, perform an XMODEM upload of the new modem firmware hex
file (e.g., 206s4712.S37) from the host computer to the modem RAM
using industry standard communications software or an equivalent
process. If downloading existing firmware from the modem, using an
industry standard communications software or equivalent, put the host
PC in XMODEM receive mode.
8. The messages described in Table 1-1 may occur during the uploading
process:
Table 1-1. Upload Messages
Message Description
Device not supported Displayed if the FLM used does not support the flash
memory that is installed on the board.
Wrong S37 format Displayed if the modem firmware being uploaded is not in
Motorola S3 format.
Record error Displayed if there is an error while either uploading or
downloading. If this occurs, the transfer should be aborted,
and the user should restart at step .5
Download abort Displayed if the transfer is aborted before it is finished. If this
occurs, the user should restart at step 5.
Erase fail Displayed if the FLM is unable to erase the flash memory. If
this occurs, the user should restart at step 5.
Download error, Re-
Load
Displayed if there was an error when uploading or
downloading. If this occurs, the user should restart at step 5.
Error, No H/W flow ctl Displayed if RTS-CTS flow control is not set. If this occurs,
the user should restart at step 3.
DTE timeout Displayed if the DTE has stopped the XMODEM transfer
process before it is finished. If this occurs, the user should
restart at step 5.
Code doesn’t match
Hardware
Displayed if the user is attempting to upload a firmware that
either not the same model (parallel, serial, etc.), crystal
frequency, or size (1Mbit, 2Mbit, etc.) as the firmware that is
currently on the board. If this occurs, the FLM will abort and
not allow the user to continue.
Device successfully
Programmed
Displayed by the FLM at the completion of a successful
upload or download then the modem will do a cold start.
The uploader and downloader flash load modules (FLM) have several built in safety
mechanisms to reduce the risk of a failed flash upload/download. The FLM will not allow
a user to upload a firmware of different model (serial, parallel, etc.) or crystal speed than
what is currently in the flash memory. Also, it will not allow the user to upload a firmware
that is larger in size than the flash memory itself (e.g., a 2Mbit firmware onto a 1Mbit flash
memory). It will, however, allow the user to upload a firmware that is smaller in size than
the flash memory, and it will program the firmware with the appropriate offset in order for
the firmware to function properly. In the instance that there is a failure during the
download or upload process, the modem will be in a “flash rescue mode”. In this mode,
the modem will respond “OK” to all AT commands, but will only take action on the AT**
command, so a new attempt to upload or download can be initiated. When the modem is
in the “flash rescue mode” it will only be able to respond to AT commands if the DTE rate
has not been changed since the last AT** command was successfully issued, even if the
modem is powered off and on.

Chapter 1 – AT Commands, S-Registers and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 11
DTE-Modem Interface Commands
The parameters defined in this section control the operation of the interface between the DTE and
modem.
Command: E Command Echo
Description: The modem enables or disables the echo of characters to the DTE. The
parameter value, if valid, is written to S14 bit 1.
Default: 1
Defined Values: E0 Disables command echo.
E1 Enables command echo.
Result Codes: OK
Otherwise ERROR
Command: Q Quiet Result Code Control
Description: Enables or disables the sending of result codes to the DTE. The parameter
value, if valid, is written to S14 bit 2.
Default: 0
Defined Values: Q0 Enables result codes to the DTE.
Q1 Disables result codes to the DTE.
Result Codes: OK
Otherwise ERROR
Command: V Result Code Form
Description: Selects the sending of short-form or long-form result codes to the DTE.
The parameter, if valid, is written to S14 bit 3.
Default: 1
Defined Values: V0 Enables short-form (terse) result codes. Line feed is not issued
before a short-form result code.
V1 Enables long-form (verbose) result codes.
Result Codes: OK
Otherwise ERROR
Command: W Connect Message Control
Description: This command, in conjunction with S95 bits 0, 2, 3, and 5 (bits 2, 3, and 5
can be written directly by the host or by the +MR, +ER, and +DR
commands, respectively), control the format of CONNECT messages. The
actual result code messages reported reflect the W command setting and
the S95 bit settings. (Also see +MR, +ER, and +DR commands.) The W
parameter value, if valid, is written to S31 bits 2 and 3.
Default: 0
Defined Values: W0 Upon connection, the modem reports only the DTE speed (e.g.,
CONNECT 19200). Subsequent responses are disabled.
W1 Upon connection, the modem reports the modulation, line speed, the
error correction protocol, and the DTE speed, respectively.
Subsequent responses are disabled.
W2 Upon connection, the modem reports the DCE speed (e.g.,
CONNECT 14400). Subsequent responses are disabled.
Result Codes: OK
Otherwise ERROR

Chapter 1 – AT Commands, S-Registers and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 12
Command: X Extended Result Codes
Description: Selects the subset of the result code messages used by the modem to
inform the DTE of the results of commands. Blind dialing is enabled or
disabled by country parameters. If the user wishes to enforce dial tone
detection, a "W" can be placed in the dial string (see D command). The
information below is based upon the default implementation of the X results
table.
If the modem is in facsimile mode (+FCLASS=1, 1.0, or 2), the only
message sent to indicate a connection is CONNECT without a speed
indication. See the table of Result Codes at the end of this chapter.
Default: 4
Defined Values: X0 Disables reporting of busy tones unless forced otherwise by country
requirements; send only OK, CONNECT, RING, NO CARRIER,
ERROR, and NO ANSWER result codes. Blind dialing is
enabled/disabled by country parameters. If busy tone detection is
enforced and busy tone is detected, NO CARRIER will be reported. If
dial tone detection is enforced or selected and dial tone is not
detected, NO CARRIER will be reported instead of NO DIAL TONE.
The value 000b is written to S22 bits 6, 5, and 4, respectively.
X1 Disables reporting of busy tones unless forced otherwise by country
requirements; send only OK, CONNECT, RING, NO CARRIER,
ERROR, NO ANSWER, and CONNECT XXXX (XXXX = rate). Blind
dialing enabled/disabled by country parameters. If busy tone
detection is enforced and busy tone is detected, NO CARRIER will
be reported instead of BUSY. If dial tone detection is enforced or
selected and dial tone is not detected, NO CARRIER will be reported
instead of NO DIAL TONE. The value 100b is written to S22 bits 6, 5,
and 4, respectively.
X2 Disables reporting of busy tones unless forced otherwise by country
requirements; send only OK, CONNECT, RING, NO CARRIER,
ERROR, NO DIAL TONE, NO ANSWER, and CONNECT XXXX. If
busy tone detection is enforced and busy tone is detected, NO
CARRIER will be reported instead of BUSY. If dial tone detection is
enforced or selected and dial tone is not detected, NO DIAL TONE
will be reported instead of NO CARRIER. The value 01b is written to
S22 bits 6, 5, and 4, respectively.
X3 Enables reporting of busy tones; send only OK, CONNECT, RING,
NO CARRIER, ERROR, NO ANSWER, and CONNECT XXXX. Blind
dialing is enabled/disabled by country parameters. If dial tone
detection is enforced and dial tone is not detected, NO CARRIER will
be reported. The value 110b is written to S22 bits 6, 5, and 4,
respectively.
X4 Enables reporting of busy tones; send all messages. The value 111b
is written to S22 bits 6, 5, and 4, respectively.
Result Codes: OK
Otherwise ERROR

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 13
Command: &C RLSD (DCD) Option
Description: The modem controls the RLSD output in accordance with the parameter
supplied. The parameter value, if valid, is written to S21 bit 5.
Default: 1
Defined Values: &C0 RLSD remains ON at all times.
&C1 RLSD follows the state of the carrier.
Result Codes: OK
Otherwise ERROR
Command: &D DTR (Data Terminal Ready) Option
Description: Interprets the ON to OFF transition of the DTR signal from the DTE in
accordance with the parameter supplied. The parameter value, if valid, is
written to S21 bits 3 and 4. Also, see S25.
Default: 2
Defined Values: &D0 DTR drop is interpreted according to the current &Q setting as
follows:
&Q0, &Q5, &Q6: DTR is ignored (assumed ON). Allows operation
with DTEs, which do not provide DTR.
Q1 DTR drop causes the modem to hang up. Auto-answer is not
affected.
&Q2, &Q3 DTR drop causes the modem to hang up. Auto-answer is
inhibited.
&D1 DTR drop is interpreted according to the current &Q setting as
follows:
&Q0, &Q1, &Q5, &Q6 DTR drop is interpreted by the modem as if
the asynchronous escape sequence had been entered. The modem
returns to asynchronous Command State without disconnecting.
&Q2, &Q3 DTR causes the modem to hang up Auto-answer is
inhibited.
&D2 DTR drop is interpreted according to the current &Q setting as
follows:
&Q0 through &Q6 drop caused the modem to hang up. Auto-answer
is inhibited.
&D3 DTR drop is interpreted according to the current &Q setting as
follows:
&Q0, &Q1, &Q5, &Q6 DTR drop causes the modem to perform a soft
reset as if the Z command were received. The &Y setting determines
which profile is loaded.
&Q2, &Q3 DTR drop causes the modem to hang up. Auto-answer is
inhibited.
If &Q5, &Q6, +FCLASS=1 or +FCLASS=2 is in effect, the action
taken is the same as for &Q0.
Command: &K Flow Control
Description: Defines the DTE/DCE (terminal/modem) flow control mechanism. The
parameter value, if valid, is written to S39 bits 0, 1, and 2.
Default: 3 (for data modem modes)
Defined Values: 0 Disables flow control.
3 Enables RTS/CTS flow control.
4 Enables XON/XOFF flow control.
5 Enables transparent XON/XOFF flow control.
Note: Upon reset, both RTS/CTS and XON/XOFF flow control is enabled
for fax modem and voice modes.
Result Codes: OK
Otherwise ERROR

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 14
Command: &R RTS/CTS (Request to Send/Clear to Send) Option
Description: This selects how the modem controls CTS. CTS operation is modified if
hardware flow control is selected (see &K command). The parameter
value, if valid, is written to S21 bit 2.
Default: None
Defined Values: &R0 In sync mode, CTS tracks the state of RTS; the RTS-to-CTS delay is
defined by S26. In async mode, CTS is normally ON and will turn
OFF only if required by flow control.
&R1 In sync mode, CTS is always ON (RTS transitions are ignored).
Tracks the state of RTS; In async mode, CTS is normally ON and will
turn OFF only if required by flow control.
Result Codes: OK
Otherwise ERROR
Command: &S DSR (Data Set Ready) Override
Description: Selects how the modem will control DSR. The parameter value, if valid, is
written to S21 bit 6.
Default: 0
Defined Values: &S0 DSR will remain ON at all times.
&S1 DSR will become active after answer tone has been detected and
inactive after the carrier has been lost.
Result Codes: OK
Otherwise ERROR
Command: +IPR Fixed DTE (Data Terminal Equipment) Rate
Description: This numeric extended-format parameter specifies the data rate at which
the modem will accept commands during online operation. It may be used
to select operation at rates at which the modem is not capable of
automatically detecting the data rate being used by the DTE. Specifying a
value of 0 disables the function and allows operation only at rates
automatically detectable by the modem. The specified rate takes effect
following the issuance of any result code(s) associated with the current
command line.
The <rate> specified does not apply in Online Data State if Normal Mode
(Direct Mode) of operation is selected.
Default: None
Defined Values: <rate> Specifies the DTE-modem interface operation rate in bits/s.
The available rates are 0, 300, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 115200, or 230400.
If unspecified or set to 0, automatic detection is selected and the character
format is also forced to autodetect, +ICF=0.
If the rate specified is not supported by the modem, an ERROR result code
will be returned.
Report Commands: +IPR? Reports current rates
+IPR=? Reports current range Example: +IPR:
(0,300,1200,2400,4800,9600,19200,38400,57600,115200, 230400)

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 15
Command: +IFC DTE-Modem Local Flow Control
Description: This extended-format compound parameter controls the operation of local
flow control between the DTE and the modem during the data state when
V.42 error control is used, or when fallback to non-error control mode is
specified to include buffering and flow control.
It accepts two numeric subparameters.
Default: 2
Defined Values: Values defined by <modem_by_DTE>Specifies the method to be used
by the DTE to control the flow of received data from the modem.
+IFC0 None
+IFC1 XON/XOFF on transmitted data (XON/XOFF on transmit data);
do not pass XON/XOFF characters to the remote modem.
+IFC2 Circuit 133 (Ready for Receiving).
+IFC3 DC1/DC3 on circuit 103 (Transmitted Data) with DC1/DC3
characters being passed through to the remote DCE in addition
to being acted upon for local flow control.
Values defined by <DTE_by_modem>Specifies the method to be used
by the modem to control the flow of transmitted data from the DTE.
+IFC0 None.
+IFC1 XON/XOFF on received data.
+IFC2 CTS/RTS.
Report Commands: +IFC? Reports the current or selected values
Response: +IFC: <modem_by_DTE>,<DTE_by_modem>
Example: +IFC: 2,2 For the defaults.
+IFC=? Reports the supported range of parameter values
Response: +IFC: (<modem_by_DTE> range),(<DTE_by_modem> range)
Example: +IFC: (0-3),(0-2).
Command: +ILRR DTE-Modem Local Rate Reporting
Description: This extended-format numeric parameter controls whether or not the
extended-format +ILRR:<rate> information text is transmitted from the
modem to the DTE.
Default: 0
Defined Values: +ILRR0 Disables reporting of local port rate (+ILRR: is not transmitted).
+ILRR1 Enables reporting of local port rate (+ILRR: is transmitted).
Report Commands: +ILRR? Reports current value
+ILRR=? Reports supported range of parameter values
Reported Rate: The <rate> reported represents the current (negotiated or renegotiated)
DTE-modem rate. If enabled, the intermediate result code is transmitted
after any modulation, error control or data compression reports are
transmitted, and before any final result code (e.g., CONNECT) is
transmitted. The <rate> is applied after the final result code is transmitted.
The DTE-modem port rate will change only if neither buffered mode nor
error controlled means are enabled (+ES=x,0) and if the negotiated carrier
rate (+MRR) does not match the current DTE-modem port rate
(autodetected from the previous command line).

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 16
Call Control Commands
Command: D Dial
Description: Directs the modem to go on-line, dial according to the string entered and
attempt to establish a connection. If no dial string is supplied, the modem
will go on-line and attempt the handshake in originate mode.
Note: If the ATD command is issued before the S1 register has cleared,
the modem will respond with the NO CARRIER result code.
If +FCLASS=0 is selected, the modem will behave as a data modem and
will attempt to connect to another data modem. The modem will have up to
the period of time specified by register S6 or S7 to wait for carrier and
complete the handshake. If this time expires before the modem can
complete the handshake, the modem will go on-hook with the NO
CARRIER response. This command will be aborted in progress upon
receipt of any DTE character before completion of the handshake.
If +FCLASS=1, 1.0, or 2 is selected, the modem will behave as a facsimile
modem and attempt to connect to a facsimile machine (or modem) by
entering the HDLC V.21 channel 2 receive state (as if +FRH=3 had been
issued). This command will be aborted upon receipt of any DTE character
if the modem has not finished dialing. In this case, the modem will go on-
hook and return to command mode after displaying the NO CARRIER
message. If the modem has finished dialing, it proceeds as if the +FRH=3
command has been issued. (Refer to the +FRH command to determine
how the modem behaves following this stage.)
Dial Modifiers
The valid dial string parameters are described below. Punctuation
characters may be used for clarity, with parentheses, hyphen, and spaces
being ignored.
Defined Values: Character string <string> corresponding to the selected option(s).
0-9 DTMF digits 0 to 9.
* The 'star' digit (tone dialing only).
# The 'gate' digit (tone dialing only).
A-D DTMF digits A, B, C, and D. Some countries may prohibit sending of
these digits during dialing.
L Re-dial last number: the modem will re-dial the last valid telephone
number. The Lmust be immediately after the Dwith all the following
characters ignored).
P Select pulse dialing: Pulse Dialing is used in the dialed numbers that
follow until a Tcommand is encountered. Affects current and
subsequent dialing. Some countries prevent changing dialing modes
after the first digit is dialed.
T Select tone dialing: Tone Dialing is used in the dialed numbers that
follow until a Pis encountered. Affects current and subsequent
dialing. Some countries prevent changing dialing modes after the
first digit is dialed.
R This command will be accepted, but not acted on.
S=n Dial the number stored in the directory (n = 0 to 3). (See &Z.)
! Flash: the modem will go on-hook for a time defined by the value of
S29. Country requirements may limit the time imposed.
W Wait for dial tone: the modem will wait for dial tone before dialing the
digits following "W". If dial tone is not detected within the time
specified by S7 (US) or S6 (W-class), the modem will abort the rest
of the sequence, return on-hook, and generate an error message.
@ Wait for silence: the modem will wait for at least 5 seconds of silence
in the call progress frequency band before continuing with the next
dial string parameter. If the modem does not detect these 5 seconds

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 17
of silence before the expiration of the call abort timer (S7), the
modem will terminate the call attempt with a NO ANSWER message.
If busy detection is enabled, the modem may terminate the call with
the BUSY result code. If answer tone arrives during execution of this
parameter, the modem handshakes.
& Wait for credit card dialing tone before continuing with the dial string.
If the tone is not detected within the time specified by S7 (US
models) or S6 (W-class models), the modem will abort the rest of the
sequence, return on-hook, and generate an error message.
, Dial pause: the modem will pause for a time specified by S8 before
dialing the digits following ",".
; Return to command state. Added to the end of a dial string, this
causes the modem to return to the command state after it processes
the portion of the dial string preceding the ";". This allows the user to
issue additional AT commands while remaining off-hook. The
additional AT commands may be placed in the original command line
following the ";" and/or may be entered on subsequent command
lines. The modem will enter call progress only after an additional dial
command is issued without the ";" terminator. Use "H" to abort the
dial in progress, and go back on-hook.
^ Toggles calling tone enable/disable: applicable to current dial
attempt only.
( ) Ignored: may be used to format the dial string.
- Ignored: may be used to format the dial string.
<space> Ignored: may be used to format the dial string.
<i> Invalid character: will be ignored.
> If enabled by country specific parameter, the modem will generate a
grounding pulse on the EARTH relay output.
Command: T Set Tone Dial Default
Description: Forces DTMF dialing until the next P dial modifier or P command is
received. The modem will set an S-Parameter bit to indicate that all
subsequent dialing should be conducted in tone mode. The DP command
will override this command. Clears S14 bit 5.
This command may not be permitted in some countries. (See P.)
Result Code: OK
Command: P Set Pulse Dial Default
Description: Forces pulse dialing until the next T dial modifier or T command is
received. Sets S14 bit 5.
As soon as a dial command is executed which explicitly specifies the
dialing mode for that particular call (e.g., ATDT...), this command is
overridden so that all future dialing will be tone dialed. (See T command.)
This command may not be permitted in some countries.
Result Code: OK

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 18
Command: A Answer
Description: The modem will go off-hook and attempt to answer an incoming call if
correct conditions are met. Upon successful completion of answer
handshake, the modem will go on-line in answer mode. This command
may be affected by the state of Line Current Sense, if enabled. (Most
countries do not require Line Current Sense.) Operation is also dependent
upon +FCLASS command and country-specific requirements.
If +FCLASS=0 is selected, the modem will enter the Connect state after
exchanging carrier with the remote modem. If no carrier is detected within
a period specified in register S7, the modem hangs up. Any character
entered during the connect sequence will abort the connection attempt.
If +FCLASS=1, 1.0, or 2 is selected, the modem will go off-hook in V.21
answer mode. It will generate the V.21 2100 Hz answer tone for 3 ± 0.5
seconds and, following a delay of 70 ms, will proceed as if the +FTH=3
command were issued. At any stage up to (but excluding) the +FTH=3
command state, any character will abort the communication. (See the
description of the +FTH command for details.)
Command: H Disconnect (Hang-Up)
Description: Initiates a hang up sequence. This command may not be available for
some countries due to PTT restrictions.
Default: None
Defined Values: H0 The modem will release the line if the modem is currently on-line,
and will terminate any test (AT&T) that is in progress. Country
specific, modulation specific, and error correction protocol specific
(S38) processing is handled outside of the H0 command.
H1 If on-hook, the modem will go off-hook and enter command mode.
For US models, the modem will remain off-hook. For global models,
the modem will return on-hook after a period of time determined by
S7.
Result Codes: OK
Otherwise ERROR
Command: O Return to Online Data Mode
Description: Determines how the modem will enter the online data mode. If in the online
command mode, the modem enters the online data mode with or without a
retrain. If in the off-line command mode (no connection), the modem
reports ERROR.
Default: None
Defined Values: O0 Enters on-line data mode without a retrain.
Handling is determined by the Call Establishment task. Generally, if
a connection exists, this command connects the DTE back to the
remote modem after an escape (+++).
O1 Enters on-line data mode with a retrain before returning to on-line
data mode.
O2 Fast retrain without speed change (used for diagnostic purpose
only).
O3 Renegotiate rate without speed change (used for diagnostic purpose
only.
O4 Renegotiate rate down one speed (used for diagnostic purpose
only).
O5 Renegotiate rate up one speed (used for diagnostic purpose only).
Result Codes: OK
Otherwise ERROR (or if not connected)

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 19
Command: L Speaker Volume
Description: Sets the speaker volume control. The parameter value, if valid, is written to
S22 bits 0 and 1.
Default: 1
Defined Values: L0 Low volume.
L1 Low volume. (Default.)
L2 Medium volume.
L3 High volume.
Result Codes: OK
Otherwise ERROR
Command: M Speaker Control
Description: Selects when the speaker will be on or off. The parameter value, if valid, is
written to S22 bits 2 and 3.
Default: 1
Defined Values: M0 Speaker is always off.
M1 Speaker is on during call establishment, but off when receiving
carrier. (Default.)
M2 Speaker is always on.
M3 Speaker is off when receiving carrier and during dialing, but on
during answering.
Result Codes: OK
Otherwise ERROR
Command: &G Select Guard Tone
Description: Causes the modem to generate the guard tone selected by this command
(DPSK modulation modes only). The parameter value, if valid, is written to
S23 bits 6 and 7.
This command may not be permitted in some countries.
Default: 0
Defined Values: &G0 Disables guard tone. (Default.)
&G1 Disables guard tone.
&G2 Selects 1800 Hz guard tone.
Result Codes: <value> = 0 to 2
Otherwise ERROR
Command: &P Select Pulse Dial Make/Break Ratio
Description: Determines the make/break ratio used during pulse dialing. The default is
country-dependent. The parameter value, if valid, is written to S28 bits 3
and 4.
Default: 0
Defined Values: &P0 Selects 39%-61% make/break ratio at 10 pulses per second.
&P1 Selects 33%-67% make/break ratio at 10 pulses per second.
&P2 Selects 39%-61% make/break ratio at 20 pulses per second.
&P3 Selects 33%-67% make/break ratio at 20 pulses per second.
Result Codes: OK
Otherwise ERROR

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Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C) 20
Command: &V Display Current Configuration and Stored Profiles
Description: Reports the current (active) configuration, the stored (user) profiles, and
the first four stored telephone numbers. The stored profiles and telephone
numbers are not displayed if the NVRAM is not installed or is not
operational as detected by the NVRAM test during reset processing.
Result Code: OK
Example: AT&V
ACTIVE PROFILE:
B1 E1 L1 M1 N0 QO T V1 W0 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5
&R1 &S0 &T5 &X0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002
S07:050 S08:002 S09:006
S10:014 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007
S38:020 S46:138
S48:007 S95:000
STORED PROFILE 0:
B1 E1 L1 M1 N0 QO T V1 W0 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5
&R1 &S0 &T5 &X0
S00:000 S02:043 S06:002 S07:050 S08:002 S09:006 S10:014
S11:095 S12:050 S18:000
S36:007 S40:104 S41:195 S46:138 S95:000
STORED PROFILE 1:
B1 E1 L1 M1 N0 QO T V1 W0 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5
&R1 &S0 &T5 &X0
S00:000 S02:043 S06:002 S07:050 S08:002 S09:006 S10:014
S11:095 S12:050 S18:000
S36:007 S40:168 S41:195 S46:138 S95:000
TELEPHONE NUMBERS:
0 = 1 =
2 = 3 =
OK.