Siemens SANTIS-ab User Manual page 18

PABX-Switch
Command-No / Meaning
320 address selection
If both the a/b-interfaces are connected to a PABX, this parameter
should be set to '1'.
Restrictions:
NT+2ab/CA restr.: Can only be set by authorized persons.
Pairgain: Automatically set to '1' and can not be changed.
18
Parameter value
0 = standard
1 = PABX
Default
0