Understood. I edited the post, lest it confuses someone in the future.
So I checked the main office Voice Services -> OBiTalk Service -> InboundCallRoute: ph,ph2 is set correctly. I called it with my own OBi at home, and it rang okay.
I'm not sure how to verify that OBiTALK service is enabled on the branch office OBi, but my guess is that it is - All of the settings under Voice Services -> ObiTALK Service are set to "OBiTALK Settings". Also, the OBiTALK service status says "Normal (User Mode)" under the system status info.
I noticed that under my LINE->InboundCallRoute field, there is a red exclamation point next to it. Is this an indication of a syntax error? Again, the field contains:
{ph1,ph2,pp(ob5009124XX)}
For privacy, I changed the last 2 digits above to XX. I have verified several times that I have the correct main office OBi device # there. Seems strange that it doesn't work.