2.AT COMMAND SET
The AT command set for the modem. The command result code is "always "OK "unless stated otherwise in the command description.
A/ - Re-execute Command
The A/ command instructs the modem to re-execute the last AT command. It will repeat the command already in the command buffer. This command does not require AT prefix and does not have to be followed by the terminator character. This command is mostly used to redial the last number in case of a busy signal.
AT= x - Write to Selected S-Register
This command writes the value x to the currently selected S-Register. An S-Register can be selected by using the ATSn command.
AT? - Read Selected S-Register
This command reads and displays the selected S-Register. An S-Register can be selected by using the ATSn command.
A - Answer
This command instructs the modem to go off-hook and answer an incoming call. After a successful connection the modem will go on-line in the answer mode. The execution of this command is affected by +FCLASS command settings. This command must be the last on the command line. All characters before the end of the line are discarded.
If +FCLASS=0 is selected, The modem will try to establish data connection with the remote modem.
Upon successful connection The modem will go on-line and issue a CONNECT result code. If connection is not established within a time specified by S7 register, The modem will go on hook and issue a NO CARRIER result code. Any character sent to the modem after A command but before CONNECT result code will abort the connection.
If +FCLASS=1 is selected, The modem will go off-hook in V.21 answer mode. It will generate the V.25 answer tone followed by V.21 modulation as if +FTH=3 command were issued.
Bn - CCITT/Bell
This command is included for compatibility only. The modem does not support Bell standards. n = 0 Returns OK result code.
n =/ 0 Returns ERROR result code
Cn - Carrier Control
This command is included for compatibility only. n = 1 Returns OK result code.
n =/ 1 Returns ERROR result code