Siemens SIMATIC Rack PC 840 V2 Operating Instructions Manual page 103

Adapter for COM1
You can convert the COM1 port of the SIMATIC PC family into the usual 25-pin male
connector by means of the enclosed adapter (25-pin / 25-pin). For this, you only have to plug
the adapter onto the COM1 socket and secure it with the two hexagonal head screws.
COM 2 Serial Port (V24/Mouse), X31
The serial port (COM 2) has the following pinout:
COM 2 Serial Port (V24/Mouse)
Pin No.
1
2
3
4
5
6
7
8
9
SIMATIC Rack PC 840 V2
Operating Instructions, Edition 05/2006, A5E00248055-04
Abbreviations Meaning
DCD (M5) Receiving signal level carrier
RxD (D2) Received data
TxD (D1) Transmitted data
DTR (S1) Data terminal ready
GND (E2) Functional ground (reference potential) –
DSR (M1) Ready for operation
RTS (S2) Request to send
CTS (M2) Clear to send
RI (M3) Incoming call
Detailed descriptions
16.1 Motherboard
Input /Output
Input
Input
Output
Output
Input
Output
Input
Input
16-5