1. When you get a call by other means (on OBiTALK, GV, a SIP service, etc.) does phone connected to OBi ring?
2. With the OBi powered off, does a call to your cellphone ring the phone connected to the OBi?
3. What, if anything, shows in Call History, with OBi powered back on and a call is made to your cell?
If (1) and (2) are ok, but (3) shows nothing, try setting LINE Port->RingThreshold down to 19.35-23.65.