Siemens SIMATIC Panel PC 870 Equipment Manual page 98

Hardware Information
Serial port COM1 (PLC/V24/Modem), X30
The serial port (COM 1) on the computing unit is assigned as follows:
Connector
1
13
Gender changer for COM1
You can convert the COM1/V24/PLC port of the SIMATIC PC family into a 25-pin
male connector by means of the enclosed gender changer (25-pin/25-pin). Plug the
gender changer onto the COM1socket and secure it with the two hexagon head
screws.
The V24 and TTY interfaces of COM1 can be used alternatively.
7-8
Pin Short
No. Name
1 –
2 TxD (D1)
3 RxD (D2)
4 RTS (S2)
5 CTS (M2)
14
6 DSR (M1)
7 GND (E2)
8 DCD (M5)
9 +TTY RxD
10–17 NC
18 +TTY TxD
19 +20 mA
25
20 DTR (S1)
21 -TTY TxD
22 RI (M3)
23-25 NC
Meaning
Shield
Serial send data
Serial receive data
Request To Send
Clear To Send
Data Set Ready
Station Ground (reference
potential)
Data Carrier Detect (car-
rier)
TTY Receive
Not Connected
TTY Send
Isolated power supply
Data Terminal Equipment
Ready
TTY Send
Incoming call
Not Connected
Panel PC 870 Computing Unit Equipment Manual
Input /
Output
–
Output
Input
Output
Input
-
Input
Input
–
Output
-
Output Output
Input
-
Edition 12/01