EXM-31 Hardware Reference
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AT Commands
AT commands are issued from an asynchronous DTE, such as a PC, and control the
modem’s operating and software configuration. The following section lists all AT
commands supported by the AT&T HSM Complete Chip Set. The defaults for each
command are in bold.
Initialization Strings
Initialization strings are used to initialize the modem before beginning to dial a
number. One of the most common is to return the modem to the factory default
values:
AT&F&W0
This command loads the factory default settings stores them as the active user profile
#0 into one of the two nonvolatile stored profile memory locations. Other commands
can be used in tandem, in addition to, or mixed.
Basic AT Commands
A/
Repeat Last Command
This command re-executes last command string (not to be preceded with AT or
followed by pressing the Return key.)
A Answer
Command
This command instructs the modem to go off-hook and attempt to establish a
connection without waiting for a ring.
Bn
Communication Standard Option
This command is used to configure the modem to the desired communications
standard settings at particular line speed.
B0
Selects CCITT V.22 when modem is at 1200 bits/s
Selects CCITT V.21 when modem is at 300 bits/s
B1
Selects Bell 212A when modem is at 1200 bits/s