User Manual

User's Manual

AT Commands

Modem operation is controlled by AT commands. These AT commands include the following:

• Basic AT commands, for example ATDT123

• Extended AT Commands for example AT&E,AT\A,AT%C,AT+MS

• S-Register commands, for example ATS32=8

• Fax Class 1 commands, for example AT+FTM

• Voice commands, for example AT#VTX

The command syntax and operation guidelines for each command category are described in

the following sections.

A command line is a string of characters sent from a DTE (Terminal or Data Terminal

Equipment) to the DCE while the DCE is in command state. Command lines have a prefix, a

body and a terminator. The prefix consists of the ASCII characters AT or at. The body

consists of printable ASCII characters. Space characters other than <CR> (See register S3),

and <BS> (See register S5) are ignored. <CR> is command terminator.

Characters preceding the AT prefix are ignored.

AT Command Guidelines

• Basic AT commands consist of single ASCII characters, which may be preceded by a

prefix character, for example &, and followed by a decimal number, for example AT&W1.

• Missing decimal parameters are interpreted as 0. For example, if you type ATH, the

command ATH0 is assumed.

• Fax commands are preceded with the +F characters and terminated by semicolon (;) or

<CR> character.

• The modem supports editing command lines by recognizing the <BS> character.

• The AT command sequence may be followed by any number of commands in sequence,

with the exception of commands Z, D or A, where all characters following on the same

command line will be ignored.

• When a syntax error is found in the command line, an ERROR response will be returned

to the DTE. Execution of commands D and A will be aborted if another character is

entered before completion of the handshake.

• When the modem has entered on-line data mode, it is possible to break the data

transmission in order to issue more AT commands. This is done by the DTE sending a

sequence of three escape characters (defined in S2, ‘+’ by default).

AT Command Set

The modem will comply with the commands listed below. Parameters applicable to each

command are listed below.

Default factory configuration settings are marked by an asterisk *.

Features marked with (-) are not yet available in the current version.

Basic AT Commands

A/ Re-execute Command

The modem repeats the last command line sent by the DTE. Usually used for re-dialing.

Note: This command should not be terminated by <CR>.