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LEONARDO 56
3.
MODEM AT COMMAND SET
The modem support AT commands set to define the configuration, initiate or
terminate modem communication, test the modem and the communication
link. The modem will work in two basic operations: command mode and
data mode.
Command mode is when the modem is not connected to another modem,
therefore "Off Line" or in a idle condition. In this mode the modem will accept
commands beginning with AT prefix. Data mode is when the modem is
connected to another modem, that is an "On Line" condition or functioning. In
this mode all the characters sent from computer are interpreted as data and
they are sent to the remote modem. You may switch from data to command
mode by entering an escape sequence. The default escape sequence is +++
this must have at least one second before and after being keyed. To go back
into data mode simply type ATO.
Data Length
Each caracter of the AT command must be an ASCII code with any of the
following format combinations:
START BIT
DATA BIT
1
7
1
8
1
7
1
8
The modem will accept even, odd, mark, or space.
3.1.
AT COMMAND SET DESCRIPTION
AT
Attention
All the characters following the letters 'AT' are commands. In AT command
mode the modem automatically detects the computer speed and parity format.
The modem will response using the same speed and parity format of AT
command.
ATA
Answer incoming data call
Cause the modem to go off hook and attempt a handshake in answer mode.
A/
Repeat last command
Cause the modem to repeat the last AT command. This command is neither
preceded by AT not followed by CR.
Modem AT Command Set
PARITY
STOP BIT
TOT
1
1
10
0
1
10
0
2
10
1
1
11
3.1
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