Data Set Ready - 3Com Courier Reference

8-2 C 8: C
HAPTER ONTROLLING

Data Set Ready

EIA-232
SIGNALING
For your modem to
Respond normally to the DTR signal and reset on DTR drop.
The Courier V.Everything modem will not accept commands
until your computer sends a DTR signal. The call will end when
the DTR signal is dropped.
To change the DTR recognition time, set S-Register 25. See
Appendix A, S-Registers for more information.
Example: Sending
AT&D1
dropping DTR will enter Command Mode.
DIP switch 1 overrides the &Dn setting at power on or reset.
Under normal conditions, the Courier V.Everything modem sends a Data
Set Ready (DSR) signal to your computer when it is ready to send and
receive data.
CAUTION: Do not change the default setting of &S0 unless you know
that your installation requires a different setting. Few communications
programs, if any, will require the Couri e r V.Everything modem to control
DSR (&S1).
Use the following command to control how the modem sends the DSR
signal.
For your modem
To send the DSR signal at all times.
When originating a call, to send the DSR signal after dialing
when the Courier V.Everything modem detects the remote
analogue device's answer tone
When answering a call, to send DSR after the Courier
V.Everything mode sends its answer tone.
After sending Carrier Detect (CD), to send a pulsed DSR signal,
followed by a Clear to Send (CTS) signal. Use this option for
specialised equipment such as automatic callback units.
After sending Carrier Detect (CD), to send a pulsed DSR signal. AT&S3
To send a DSR signal to your computer at the same time the
Courier V.Everything mode
before connecting with another device,
sends the CD signal.
Command
AT&D3
Command
AT&S0 (Default)
AT&S1
AT&S1
AT&S2
AT&S4