Siemens S5-135U/155U System Manual page 530

Connector Assignments
Assignments of the front connector for the coordinators
Pin No.
10
11
12
13
14
15
11-18
Designation
1 Housing/0 V/0V
2 Receiver TTY(-)
3 Private line
4 +24 V
5 Private line
6 Transmitter TTY (+)
7 Transmitter TTY (-)
8 Housing/0 V/0V
9 Receiver TTY (+)
24 V ground (20 mA (-) current sources)
20 mA (+) current source
Private line
20 mA (+) current source
Private line
Private line
ext
ext
C79000-G8576-C199-06
System Manual