Having a strange issue.
Our setup is as follows: We are using 2 Grandstream UCM 6510 with HA, and 3 Grandstream GXW 4248 Gateways in a healthcare facility with 120 rooms (Besides for a number IP phones in the business area of the building).
Two rooms, both connected to the same gateway, are experience the following issue.
When receiving inbound calls, the caller will hear the phone ringing. The physical phone will not ring. If you pick up the phone, you can pickup the call. This only happens the first time. Call back again, and it will ring in the room. All subsequent call will ring.
Wait a couple of hours and this cycle repeats itself.
No other complaints from other rooms. Updated gateway firmware, rebooted several times, re-terminated cables, replaced phones… Can’t get to the bottom of this. Any help would be appreciated.
I found a similar post with no solution.