Siemens SIMATIC PANEL PC 877 Operating Instructions Manual page 198

Detailed descriptions
17.1 Motherboard
Serial interface COM 1, X30
The serial interface (COM 1) on the device has the following pinout:
Serial interface COM 1 (socket)
PinNo.
1
2
3
4
5
6
7
8
9
10–17
18
19
20
21
22
23–25
17-6
Abbreviation Meaning
– Shielding
TxD (D1) Serial transmit data
RxD (D2) Serial receive data
RTS (S2) Request to send
CTS (M2) Clear to send
DSR (M1) Ready for operation
GND (E2) System ground (reference
potential)
DCD (M5) Data carrier detect
– –
– Not assigned
– –
– –
DTR (S1) Data terminal ready
– –
RI (M3) Incoming call
– Not assigned
Input/Output
–
Output
Input
Output
Input
Input
–
Input
–
–
–
–
Output
–
Input
–
Operating instructions, Release 07/2006, A5E00877780-01
SIMATIC Panel PC 877