Table of Contents
Advertisement
3 AT Commands
The Data Terminal Ready (DTR) signal on pin 20 of the RS-232/V.24 interface must be high, or "on," in
order for the modem to operate. A high DTR signal tells the modem that the computer it is connected to is
ready to communicate through the modem.
The DTR signal can also be used to cause the modem to reset to its default parameters, as if you had given
the modem an ATZ command.
&D0 (or &D) causes the modem to ignore the DTR signal and treat it as always on.
&D1 causes the modem, if in online data mode, to enter command mode, issue an OK and remain
connected when the DTR drops.
&D2 causes the modem to hang up when DTR drops while the modem is in online data mode.
&D3 causes the modem to reset when DTR drops . It will also hang up if it is online.
&Sn
Data Set Ready Control
n = 0 or 1
Default: &S0
Use the &S command to control the state of the Data Set Ready (DSR) signal on the RS-232/V.24 interface.
Normally, DSR follows CD. You can force the signal high or allow it to act normally.
&S0 forces DSR high (on).
&S1 allows DSR to act normally, that is, to follow CD.
CommPlete Communications Server
25
Advertisement
Table of Contents
