Siemens SIMATIC NET PROFIBUS Owner's Manual page 148

Passive Components for RS-485 Networks
Table 4-10 Pinout of the Sub D Connector
Pin Signal
1 PE
2 NC
3 B (RXD/TXD-P)
4 NC
5 M5V2 (DGND)
6 P5V2 (VP)
7 NC
8 A (RXD/TXD-N)
9 NC
4-50
Meaning
Protective earth
Not used
Data line B (receive/transmit data P)
Not used
Data ground
+ 5V voltage plus
Not used
Data line A (receive/transmit data N)
Not used
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000