Siemens S5-155U System Manual page 237

Interface Submodule
5 - 88
If you unplug the jumpers 12-14 and 4-6, the two-wire line R is not
preset and the break state cannot be recognized clearly.
With the following jumper setting you can switch over the data
direction on the two-wire line R:
Jumper 16-18: setting for full duplex operation. Data can only be
received on the two-wire line R (default).
Jumper 18-12: setting for half duplex operation. Data can be
transmitted or received on the two-wire line R (special driver
required).
With the following jumper setting you can switch the two-wire line B
as an input or an output.
Jumper 17-19: two-wire line B is switched as an output. The line
X(B) can be used as an input. X(A) is connected to ground (default).
Jumper 15-17: two-wire line B is switched as an input. The line X(B)
cannot be used.
With the following jumper setting you can either place the signal /PS3
or the internal transmitting frequency (TxCint) on the two-wire line B.
The two-wire line B must be switched as an output.
Jumper 2-4: the signal /PS3 can be transmitted via the two-wire line
B (default).
Jumper 4-6: the internal transmitting frequency TxCint can be trans-
mitted via the two-wire line B.
System Manual
C79000-B8576-C199-03