I assume you meant to ask about conference calling (3-way calling) for inbound. It's not supported via Google Chat, which is what the OBi is using. It can only do call-waiting, via a hook-flash, which will swap between the two calls. You can, however, make a 3-way conference call if you start with an outbound call via your OBi-attached phone, then hit flash, dial the other party, answer, and hit flash again.