Siemens SIMATIC S7-200 System Manual page 536

S7-200 Specifications
Table A-40 Pin-outs for RS-485 to RS-232 DCE Connector
RS-485 Connector Pin-out
Pin
Number
1 Ground (RS-485 logic ground)
2 24 V Return (RS-485 logic ground)
3 Signal B (RxD/TxD+)
4 RTS (TTL level)
5 Ground (RS-485 logic ground)
6 +5 V (with 100
7 24 V Supply
8 Signal A (RxD/TxD-)
9 Protocol select
Table A-41 Pin-outs for RS-485 to RS-232 DTE Connector
RS-485 Connector Pin-out
Pin
Number
1 Ground (RS-485 logic ground)
2 24 V Return (RS-485 logic ground)
3 Signal B (RxD/TxD+)
4 RTS (TTL level)
5 Ground (RS-485 logic ground)
6 +5 V (with 100
7 24 V Supply
8 Signal A (RxD/TxD-)
9 Protocol select
1
A conversion from female to male, and a conversion from 9-pin to 25-pin is required for modems
A-92
Signal Description
Ω
series resistor)
Signal Description
Ω
series resistor)
RS-232 DCE Connector Pin-out
Pin
Signal Description
Number
1 Data Carrier Detect (DCD) (not used)
2 Receive Data (RD)
(output from PC/PPI cable)
3 Transmit Data (TD)
(input to PC/PPI cable)
4 Data Terminal Ready (DTR)
(not used)
5 Ground (RS-232 logic ground)
6 Data Set Ready (DSR) (not used)
7 Request To Send (RTS) (not used)
8 Clear To Send (CTS) (not used)
9 Ring Indicator (RI) (not used)
RS-232 DTE Connector Pin-out
Pin
Signal Description
Number
1 Data Carrier Detect (DCD) (not used)
2 Receive Data (RD)
(input to PC/PPI cable)
3 Transmit Data (TD)
(output from PC/PPI cable)
4 Data Terminal Ready (DTR)
(not used)
5 Ground (RS-232 logic ground)
6 Data Set Ready (DSR)
(not used)
7 Request To Send (RTS)
(output from PC/PPI cable)
8 Clear To Send (CTS) (not used)
9 Ring Indicator (RI) (not used)
S7-200 Programmable Controller System Manual
1
A5E00066097-02