Siemens SANTIS-ab user manual Operating Modes, NT+2ab, Pairgain

2. Operating Modes

The connection to the public telephone network as well as the selection of one of the following three operating modes must be done by an authorized person, e.g. telecom staff:

1.	NT+2ab	S- and a/b-interfaces available
2.	NTBA	Only S-interface available
3.	Pairgain	Only a/b-interfaces available

5