These commands are very useful as diagnostic tools for today's computer professional. To use these commands, make sure the communication software is loaded and the computer is in terminal mode. Unless the modem is set up to autoconnect (online mode), it will be in command mode and ready to accept AT commands. The following table lists some of the more useful AT commands used by computer professionals.
|AT||Lets you know that your modem is plugged in and turned on.
The modem should respond with OK.
|ATE1||Echoes the command on the screen.|
|ATE0||Turns off the echo to the screen. Some modems will not run correctly when the echo is on.|
|ATH||Takes the telephone off the hook. Should elicit a reply of OK or 0 from the modem, or a dial tone and an OH indicator if it's an external modem.|
|ATM1||Turns the speaker on for the dial tone. ATL0 is the lowest volume.
ATL2 is medium volume.
|ATM0||Turns the speaker off.|
|ATD||Takes the phone off the hook and dials a number if one is included with command (for example, ATDT555-2222). The second "T" is for tone; substitute "P" for a pulse phone. Include a "W" (ATDTW) to instruct it to wait for a dial tone before dialing. Include a comma anywhere after the command to instruct it to pause before continuing to dial.|
|ATQ0||Enables result codes. A troubleshooting aid. Type "ATV1" prior to this command and you will get back verbose result codes (OK-BUSY-CONNECT 2400,9600-COMPRESSION:V.42bis).|
|ATQ1||Disables result codes.|
|ATH, ATH0||Hangs up the modem.|
|ATX||This resets your modem to a predefined state. You can configure your own reset state. If it wasn't set previously, it can be reset to the factory's default setting.|