Incoming calls on all trunks (PSTN, SP1, SP2, and OBiTALK) ring the OBi's phone by default.
Outgoing calls use a selected trunk (PSTN, SP1, SP2, or OBiTALK) by default but can be overriden using a prefix:
**1 -> SP1 Service
**2 -> SP2 Service
**8 -> PSTN Line
**9 -> OBiTALK Service
Automatic overrrides based on dialed number patterns can also be configured using custom DigitMaps.
For example:
International calls (011+) -> SP1 Service (Google Voice)
Specific area codes -> PSTN Line
Remaining area codes -> SP1 Service (Google Voice)