For example, ATM <ENTER> or ATM0 <ENTER> disables the speaker on your modem.
Each command is listed in the link table below, or you can access modem command descriptions by the following groupings:
| 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. |
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. |
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.
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. |