I have a zultys with SIP trunks.

I can see/hear at the system that it is sending out 180 RINGING.
I have verified that the SIP provider is receiving the 180 RINGING.
The verified that it is forwarding out the 180 RINGING to the PSTN.

Intermittently, the 180 RINGING gets dropped somewhere in the PSTN and the caller doesn't hear the ring back even though it is being sent on up the line. The SIP provider states it is an issue with the service provider of the calling party. In this case ATT cellular. I haven't been able to confirm if it is happening with any other carrier.


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TouchPoint Networks.

Serving the Northwest Since 1991
NEC Shoretel Zultys T3 Tadiran