Basic Commands

With the following basic AT commands, you can make calls directly, select the dialing method (tone or pulse), control the speaker volume, and perform a number of other basic modem operations. IMPORTANT: You must be in the Command mode of your communication software to use the AT commands. Refer to the documentation that came with your communications software for information on entering the Command mode.

• AT -- This prefix begins all but two commands you issue to the modem locally, and tells the modem "ATtention! commands to follow".
• D -- Dial. Use the D command to dial a telephone number from the command line. The format of the command is as follows:
  ATD [string]

  The string parameter can contain up to 45 characters, the phone number and dial modifiers. The dial modifiers instruct a modem how to place the call. Do not use any added characters, such as parentheses or hyphens in the phone number.

• +++ -- Escape Character Sequence. After you have connected to another modem, you may need to return to command mode to adjust the modem configuration, or more commonly, to hang up. To do this leave your keyboard idle (press no keys) for at least one second, then press "+" three times. This is one of the two commands that do not use the AT prefix, or a carriage return to enter. After a moment, the modem will respond with OK indicating you have been returned to Command mode.
• A/ -- Repeat. This command does not use the AT prefix nor does it require a carriage return to enter. Typing this command causes the modem to repeat the last command line entered, and is most useful for redialing telephone numbers which are busy.
• &Fn -- Factory Defaults. This command (in which n=0 or 1) returns all parameters to the selected set of factory defaults.
• H -- Hang Up. This command tells the modem to go "on-hook", or to disconnect the telephone line.
• O -- On-Line. This command returns the modem to the on-line mode and is usually used after the escape sequence (+++) to resume communication.
• Zn -- Reset Modem. This command (in which n=0 or 1) resets the modem to the configuration profile stored in non-volatile memory location 0 or 1.

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