4-2
Issue 3 April 1994
Table 4-1. AT Command and S-Register Reference (1 of 27)
AT
Command
or
S-Register
Description
+++
Escape sequence
The escape sequence allows the modem to exit Data
mode and enter online Command mode.
A/
Repeat last command
Do not precede this command with an AT prefix or
conclude it by pressing the Enter key.
A
The Answer command allows the modem to go
off-hook and attempt to answer an incoming call.
B
n
CCITT/Bell Mode
This command selects whether the modem uses the
CCITT V.21 and V.22 protocols or the Bell 103J and
212A protocols for operation at 300 or
1200 bps. It also determines whether it receives at 75
bps and transmits at 1200 bps or transmits at
75 bps and receives at 1200 bps when using
CCITT V.23 protocol. This command is used in
conjunction with the S41 register settings 7—13.
B0
V.21 or V.22 protocol
B1
Bell 103 or Bell212A protocol
B2
V.23 protocol (75 bps/1200 bps)
B3
V.23 protocol (1200bps/75 bps)
NOTE: For B2 and B3, both modems must be
configured for the same mode of operation.
