OK, I have been experiencing an odd one-way audio issue at only one location (I have several with PBXAct servers and a variety of Sangoma phones). At this point I am reaching out to the community for information to either help clarify my suspicions, or help shed some light on the mystery.
I have had a variety of Sangoma phones in about five rooms (always the same rooms) suddenly fail to play back audio on the handset, however the speaker phone works just fine. Meaning, the caller (whether internal or external) can hear the person on this phone speak, however the person on this phone can not hear the caller. It’s like the earpiece in the handset stopped working.
Factory resets, firmware upgrades (all endpoints are now at the latest 2.0.4.73), replacement handsets and cables, none of that works. We have to RMA the phone for a replacement.
Here is my suspicion, 98% of the time this problem happens shortly after a power surge or outage in the building. All of the switching gear that these phones are connected to are on rack mount TrippLite UPS units with AVR. So my question is, could there somehow be a strong enough surge that is causing and EMI pulse to be collected by the CAT 6 cabling and damaging the phones? The switches are Aruba Mobility S2500 and S300 with POE.
I welcome any information or advice, especially if you have experienced this issue yourself. I did re-terminate one of the drops just in case, however my testing equipment revealed no problems at all.