Siemens SIMATIC PANEL PC 877 User Manual
Page 198
Detailed descriptions
17.1 Motherboard
SIMATIC Panel PC 877
17-6
Operating instructions, Release 07/2006, A5E00877780-01
Serial interface COM 1, X30
The serial interface (COM 1) on the device has the following pinout:
Serial interface COM 1 (socket)
PinNo.
Abbreviation
Meaning
Input/Output
1
–
Shielding
–
2
TxD (D1)
Serial transmit data
Output
3
RxD (D2)
Serial receive data
Input
4
RTS (S2)
Request to send
Output
5
CTS (M2)
Clear to send
Input
6
DSR (M1)
Ready for operation
Input
7
GND (E2)
System ground (reference
potential)
–
8
DCD (M5)
Data carrier detect
Input
9
–
–
–
10–17
–
Not assigned
–
18
–
–
–
19
–
–
–
20
DTR (S1)
Data terminal ready
Output
21
–
–
–
22
RI (M3)
Incoming call
Input
23–25
–
Not assigned
–