Terminal Interface Commands; Data Carrier Detect - Motorola V.3400 User Manual

AT Commands
Note
If the modem is set to respond to DTR the DTR signal must
be on for autoanswer to work.

TERMINAL INTERFACE COMMANDS

The EIA-232 interface connects the modem and DTE. Terminal inter-
face commands control the action of the modem and the terminal in
response to the signals being exchanged on the interface pins. Refer to
Table 2-1.
Data Carrier Detect &C
When using DCD to indicate a valid carrier, use the &C1 command.
Some terminals and other devices require DCD on in order to communi-
cate with the modem; if so, use the &C command.
Command
&C
&C1
&C2
&C3
* default
AT&C3 is used to simulate switched carrier operation.
Note
For simulated switched carrier operation &C3 must be
selected on both modems. Not available in the B103 and
V.21 modulation modes.
5-18
DCD always on*
DCD is on when the modem recognizes remote modem
carrier or if enabled when protocol negotiation is com-
plete.
DCD on except for 5 seconds after disconnect
DCD follows RTS on remote modem (simulated
switched carrier V.13).
Operation
V.3400