Installation manual

Publication 1747-RM001G-EN-P - November 2008
SLC Communication Channels 13-87
Transmission requires all three inputs (CTS, DCD, and DSR) to be active.
Whenever DSR and DCD are both active, the modem lost bit is reset.
Half-duplex Modem without Continuous Carrier Selected - This is
exactly the same as Half-duplex Modem with Continuous Carrier except
monitoring of DCD is not performed. DCD is still required for receptions but
is not required for transmissions. Transmissions still require CTS and DSR.
The modem lost bit will only be set when DSR is inactive.
DF1 Half-duplex Master
When you configure the SLC 5/03, SLC 5/04, and SLC 5/05 processors for
DF1 half-duplex master, the following control line operation takes effect:
No Handshaking Selected - DTR is always active and RTS is always
inactive. Receptions and transmissions take place regardless of the states of
DSR, CTS, or DCD inputs. This selection should only be made when the
processor is directly connected to another DTE device.
Full-duplex Modem Selected - DTR and RTS are always active except at the
following times. If DSR goes inactive, both DTR and RTS are dropped for 1
to 2 seconds then reactivated. The modem lost bit (S:5/14) is turned on
immediately. While DSR is inactive, the state of DCD is ignored. Neither
receptions nor transmissions are performed.
If DCD goes inactive while DSR is active, then receptions are not allowed. If
DCD remains inactive for 9 to 10 seconds, then DTR is set inactive until DSR
goes inactive. At this point, the modem lost bit is also set. If DSR does not go
inactive, then DTR is raised again in 5 to 6 seconds.
Transmission requires all three inputs (CTS, DCD, and DSR) to be active.
Whenever DSR and DCD are both active, the modem lost bit is reset.
Half-duplex Modem without Continuous Carrier Selected - DTR is
always active and RTS is only active during transmissions (and any
programmed delays before and after transmissions). The processor does not
monitor DCD.
If DSR goes inactive, RTS is dropped. The modem lost bit (S:5/14) is turned
on immediately. While DSR is inactive, neither receptions nor transmissions
are performed.
Transmission requires two inputs, CTS and DSR, to be active. Whenever DSR
is active, the modem lost bit is reset.