Siemens 6AV3991-1AJ02-0AB0 Equipment Manual page 139

Configure interface The IF1B interface can be configured by using the DIL switches, located
IF1B
beside the 9–pin Sub-D connector. This interchanges the RS422 receive data
and the RTS signal. By default, the RTS signal is not required by the
communication peer.
The table shows the permissible DIL switch settings.
TP27, TP37 Equipment Manual
Release 01/00
Communication Communication
RS422/RS485
TP
PPI/MPI/PROFIBUS
TP
PPI/MPI
TP
Standard cable
Installation
Switch Setting Switch Setting
1 2 3 4
ON
PLC
OFF
1 2 3 4
ON
OFF
RTS on pin 4 (default)
1 2 3 4
ON
OFF
RTS on pin 9 (same as PU)
1 2 3 4
ON
PLC
OFF
No RTS on plug
1 2 3 4
ON
PLC
OFF
12-11