User`s guide

6: BSC 2780/3780 Link Configuration Options
DC 900-1340I 169
6.15.1 RTS Signal
When the modem control option is set to half-duplex operation (HDX-1, HDX-2, or
HDX-3), the RTS signal is turned on when BSC is ready to transmit and turned off
when transmission is complete. In full-duplex operation (FDX-1, FDX-2, or FDX-3),
the RTS signal is turned on when the link is started and stays on until the link is stopped.
In all cases, transmission does not start until a clear to send (CTS) signal is received by
the BSC software.
6.15.2 DSR Signal
The modem control option allows a link to monitor the data set ready (DSR) signal.
With the HDX-1 or FDX-1 setting, line activity ceases when the signal on the DSR pin
is lost. With either the HDX-2 or FDX-2 setting, the incoming DSR and DCD signals
are ignored by the BSC software. The HDX-2 and FDX-2 settings are useful for half-
duplex modems that toggle the DSR signal during normal link operation, or when DSR
may not be present. With either the HDX-4 or FDX-4 setting, line activity ceases when
the signal on either the DSR or DCD pin is lost. In all cases, CTS is used for permission
to send data.
Table 6–3: Modem Control Option Settings
Va lue Setting Description
0 HDX-1 Half duplex, monitor DSR
1 FDX-1 Full duplex, monitor DSR
2 HDX-2 Half duplex, ignore DSR and DCD
3 FDX-2 Full duplex, ignore DSR and DCD
4 HDX-3 Half duplex, monitor DCD
5 FDX-3 Full duplex, monitor DCD
6 HDX-4 Half duplex, monitor DSR and DCD
7 FDX-4 Full duplex, monitor DSR and DCD