Command Entry Rules


Each command is listed in the link table below, or you can access modem command descriptions by the following groupings:

Command Description Links

Command Description Command Description
+++ Escape sequence. &Z Store telephone number.
$ Basic command help. \A Select maximum MNP block size.
A Answer. \B Send break
A/ Repeat last command. \G Modem port flow control.
A> Repeat last command every S6 seconds. \X XON/XOFF pass through.
B Communication standard setting. +$ Help for dial, +P, and #CID commands.
D Dial. +A8E V.8 and V.8 bis operation control.
E Echo. +A8T Send V.8 bis signal and/or message.
H Hook control. +DCS Select data compression algorithm.
I Request ID information. +DR Data compression reporting.
L Speaker volume. +DS Data compression.
M Speaker control. +DS44 V.44 data compression.
N Modulation handshake. +EB Brake handling in error control operations.
O Return to online data mode. +ER Error control reporting.
P Select pulse dialling. +ESA Set up error control parameters.
Q Result code control. +FAA Set DCE adaptive answer mode.
S S register control +FCLASS Service class indicator.
T Select tone dialling. +FLO Set DTE-DCE flow control.
V DCE response format. +FMI Manufacturer identification.
W Result code option. +FMM Product identification.
X Extended result control. +FMR Version/revision information.
Y Select profile for hard reset. +FPR Set DTE-DCE FAX port rate.
Z Reset and recall stored profile. +FRH Receive HDLC data with n carrier.
#CID Caller ID. +FRM Receive FAX data with n carrier.
#UD Unimodem diagnostics. +FRS Receive silence.
%B View numbers in blacklist. +FTH Transmit HDLC data with carrier.
%E Auto fallback/fallforward control. +FTM Transmit FAX data with n carrier.
&$ Help for & commands. +FTS Transmission silence.
&A ARQ result codes +GCAP Request complete capabilities list.
&B Controls the serial port rate. +GCI Country of installation.
&C Data carrier detect (DCD) control. +ILRR DTE-DCE local rate reporting.
&D Data terminal ready (DTR) control. +IPR Fixed DTE rate.
&F Restore factory default configuration. +ITF Transmit flow control threshold.
&G Guard tone control. +MR Modulation reporting control.
&H Transmit Data (TD) flow control. +MS Modulation selection.
&K Data compression control. +PCW Call waiting enable.
&M ARQ control mode. +PIG PCM upstream ignore.
&N Attempt forced speed. +PMH Modem on hold enable.
&P Pulse dial make-to-break ratio selection. +PMHD Modem on hold DTMF dialling.
&S Data set ready (DSR) option. +PMHF V.92 modem on hold flash hook.
&T Self-test commands. +PMHR Initiate modem on hold.
&W Store current configuration. +PMHT Modem on hold timer.
&Y Sets break control. +PQC V.92 phase 1 and phase 2 control.
    +PSS Use short sequence.

Terminal Mode Control

These commands do not require the the AT prefix or pressing ENTER.

Command Function
+++ Escapes to online-command mode.
A/ Re-executes the last issued command. Used mainly to redial.
A> Re-executes the last issued command continuously until the user intervenes or the command is executed forever.

Command Help

The provides help commands that display high-level help. Additionally, many commands have both an option to display valid values for the variables associated with the command and an option to display the current settings of the command. Both kinds of help are described below.

Command Help Options

Most commands that have an equal sign (=) option also let you display option values. The suffix =? displays valid values, and the suffix ? displays the current option setting.

For example, in the +GCI command:

AT+GCI=?<ENTER> displays a list of valid country codes.

AT+GCI?<ENTER> displays the current country code.

The following table lists general help commands.

Command Type of Help Displayed
AT$ Basic commands.
AT&$ & commands.
AT+$ Dial commands: +P commands, and #CID commands.
ATS$ S-Registers.
AT+GCI$ List of valid commands.