Rts-Line (Rts/Cts) - Siemens SINUMERIK 840 Planning Manual

3 Interface Modules

3.3.4 RTS-LINE (RTS/CTS)

3.3.4 RTS-LINE (RTS/CTS)
The RTS-LINE transmission procedure is a line-controlled transmission method, i.e. the control
characters XON and XOFF are not required. The functions of these control characters are
carried out by the RTS and CTS signal lines. This procedure has full-duplex capabilities, i.e.
data can be transmitted and received simultaneously. As in the case of the XON/XOFF
procedure, the user need not take into consideration block lengths or data overflow. This is
managed by the procedure.
If the procedure is configured as slave, the RTS signal line is activated for reading in data only
after the "Data start" command is received. In this way, the transmitter is informed that it may
start transmitting. If the procedure is assigned the priority "master", it is activated as soon as
the RTS interface is assigned.
Depending on the configuration, the driver checks the status of the DSR line and evaluates it.
For this purpose, however, the DTR and DSR modem control lines must be connected.
DTR is set and/or reset by the CP 315; DSR, however, is merely evaluated by the CP 315. As
in the case of XON/XOFF, the end identifiers for the RTS-LINE procedure driver can be
configured. For normal applications, however, these end identifiers are not required. If the
procedure is configured "without" end identifiers, the expiry of the character monitoring time is
used as the end criterion.
Transmitter
TxD
RxD
RTS
CTS
DTR
DSR
Signal ground
Wiring for the RTS-LINE procedure
3–24
© Siemens AG 1989 All Rights Reserved
06.91
Receiver
RxD
TxD
CTS
RTS
DSR
DTR
Signal ground
6FC5 197-0AB20-0BP0
SINUMERIK 840/880 (PJ)