User's Manual

Chaper 2 AT Commands Set

AT commands are issued to DTE to control the modem's operation. AT commands

can only be entered while the modem is in command mode. Except for the A/

command and the +++ escape command, all commands must be prefixed with the

attention code AT. For instance, the “A” command (below) would be entered as:

"ATA<CR>". With out the AT prefix, the command line cannot be executed. For

example: The format for entering AT commands is “ATXn” where X is the AT

command, and n is the specific value for that command.

More than one command can be placed on a single line and (if desired) separated

with spaces for readability. Once the carriage return (Enter) key is pressed, the

command line is executed. A line with no carriage return is ignored. Any command

issued is acknowledged with a response in either text or numeric values known as

result codes. In the following, all commands, command-values and result code

recognized by the modem are shown; any entries other than those shown cause the

ERROR result code. The modem accepts either upper or lower case characters in the

command line and ignores any spaces within or between commands. Typing errors

can be corrected with the Backspace key. Exceptions are noted in the description of

specific commands.

+++AT Escape Sequence

The escape sequence allows the modem to exit data mode and enter online

command mode. While in online command mode, you may communicate directly to

your modem using AT commands. You may return to data mode by issuing the ATO

command.