7-2 CHAPTER 7: CONTROLLING EIA-232 SIGNALING
Data Set Ready 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.
Example: Issuing AT&S3 configures the Business Modem to send a
pulsed DSR signal after sending the Carrier Detect (CD) signal.
For you modem Command
To send the DSR signal at all times. AT&S0 (Default)
When originating a call, to send the DSR signal aft er dialing
when the Business Modem detects the remote analog device’s
answer tone
AT&S1
When answering a call, to send DSR after the Business Modem
sends its answer tone. AT&S1
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.
AT&S2
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. AT&S4
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).
AT&S5