At= x - write to selected s-register, At? - read selected s-register, A - answer – Perle Systems 833IS User Manual
Page 258: Bn - ccitt or bell, Cn - carrier control
AT Commands
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Perle 833IS User Guide
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. All of the S-Registers will return the
OK response if x is a number. Some registers may not be written due to country
specific PTT limitations.
Result Codes
OK
For all arguments.
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.
Result Codes:
OK
For all arguments.
A - Answer
The modem will go off-hook and attempt to answer an incoming call if correct
conditions are met. Upon successful completion of answer handshake, the modem
will go on-line in answer mode. Operation is also dependent upon +FCLASS
command and country-specific requirements.
Bn - CCITT or Bell
When the modem is configured to allow either option, the modem will select Bell or
CCITT modulation for a line speed connection of 300 or 1200 bps according to the
parameter supplied. Any other line speed will use a CCITT modulation standard.
B0
Selects CCITT operation at 300 or 1200 bps during Call Establishment
and a subsequent connection. (Default for W-class models.)
B1
Selects BELL operation at 300 or 1200 bps during Call Establishment
and a subsequent connection. (Default for US models.)
Result Codes:
OK
n = 0 or 1.
ERROR
Otherwise.
Cn - Carrier Control
This command is included for compatibility only, and has no effect other than
returning a result code. The only valid parameter is 1.
Result Codes:
OK
n = 1.
ERROR
Otherwise.