AT Command Set and S-Registers
4-12
Issue 2 May 1995
Table 4-1. AT Command Reference (11 of 18)
AT
Command Description
&C
n
CD CONTROL
This command controls the CD (Carrier Detect) signal.
&C0
State of carrier from the remote modem is ignored.
CD is always on. (Also known as Forced On.)
&C1
State of carrier from the remote modem is
tracked. CD reflects the state of the received
carrier. (Standard RS232 operation.)
&D
n
DTR CONTROL
This command controls what actions are taken by the
modem based upon the DTR (Data Terminal Ready) signal.
&D0
The modem ignores DTR and assumes it is always
active.
&D1
The modem switches from Data mode to Command
mode when an on-to-off transition of DTR is
detected. (An ATO returns the modem to Data
mode.)
&D2
The modem hangs up and switches to Command
mode when an on-to-off DTR transition is
detected. Auto-answer is disabled if DTR is low.
&D3
An on-to-off transition of DTR re-initializes the
modem but does not perform a complete power
reset.
NOTE: DTR has to remain off for a minimum amount of time
before the modem will perform any of the actions for this
command. This minimum time period is determined by the
setting of S-Register S25. If DTR is off for less than that time
period, no action is taken. See S25 for more information.
&F
LOAD FACTORY SETTINGS
This command loads the factory settings for the AT
commands and S-Registers into the Active Profile area.
NOTE: This command does not reset the )C
n command
option to its factory setting.
