3Com Courier Reference

Contents

3Com Courier Reference Manual pdf 62 page image

8-2 C HAPTER 8: C ONTROLLING EIA-232 SIGNALINGExample: Sending AT&D1 before connecting with another device,dropping DTR will enter Command Mode.DIP switch 1 overrides the &Dn setting at power on or reset.Data Set Ready Under normal conditions, the Courier V.Everything modem sends a DataSet Ready (DSR) signal to your computer when it is ready to send andreceive data.CAUTION: Do not change the default setting of &S0 unless you knowthat your installation requires a different setting. Few communicationsprograms, if any, will require the Courier V.Everything modem to controlDSR (&S1).Use the following command to control how the modem sends the DSRsignal.Respond normally to the DTR signal and reset on DTR drop.The CourierV.Everything modem will not accept commandsuntil your computer sends a DTR signal. The call will end whenthe DTR signal is dropped.To change the DTR recognition time, set S-Register 25. SeeAppendix A, S-Registers for more information.AT&D3For your modem to CommandFor your modem CommandTo send the DSR signal at all times. AT&S0 (Default)When originating a call, to send the DSR signal after dialingwhen the Courier V.Everything modem detects the remoteanalogue device’s answer toneAT&S1When answering a call, to send DSR after the CourierV.Everything mode sends its answer tone.AT&S1After sending Carrier Detect (CD), to send a pulsed DSR signal,followed by a Clear to Send (CTS) signal. Use this option forspecialised equipment such as automatic callback units.AT&S2After sending Carrier Detect (CD), to send a pulsed DSR signal. AT&S3To send a DSR signal to your computer at the same time theCourierV.Everything mode sends the CD signal.AT&S4