Data Set Ready - 3Com 56K Command Reference Manual

7-2 C 7: C
HAPTER ONTROLLING

Data Set Ready

EIA-232 S
IGNALING
Under normal conditions, the Business 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 Windows
communications programs, if any, will require the Business Modem to
control DSR (&S1).
Use the following command to control how the modem sends the DSR
signal.
For you modem
To send the DSR signal at all times.
When originating a call, to send the DSR signal after dialing
when the Business Modem detects the remote analog device's
answer tone
When answering a call, to send DSR after the Business Modem
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
specialized 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
Business Modem sends the CD signal.
To send DSR normally (with CTS) after sending CD.
In order to change the DSR pulse time (in 20-second
increments), set S-Register 24. (See Appendix B,Alphabetic
Command Summary).
Example: Issuing
AT&S3
pulsed DSR signal after sending the Carrier Detect (CD) signal.
configures the Business Modem to send a
Command
AT&S0 (Default)
AT&S1
AT&S1
AT&S2
AT&S4
AT&S5