From a recent service call
The phones told us it was the switch.
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01 — Reported
Calls breaking up.
Choppy audio across the office, on and off. A phone company alone would have checked its side and said the service was fine. It was.
Ext 104 → outside lineAudio breaking up -
02 — What we read
The phones kept the evidence.
Every desk phone records its own call-quality statistics. They showed jitter and loss arriving in bursts, and every affected phone sat behind the same switch.
Call-quality stats · from the phonesJitter in burstsAffected
Every phone behind SW-01
Carrier side
Clean
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03 — The cause
The box in the closet.
The PoE switch was producing collisions in its managed configuration. Not the phone service, not the computers. The piece in between that nobody owned.
SW-01 · PoE · managed modeCollisionsSW-01112! collisions on the ports the phones use
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04 — The point
See the whole path.
Voice is the most sensitive thing on your network. Whoever runs your phones should be able to see the switch, the firewall and the circuit, and be allowed to fix them.
One firm · the whole pathVisible end to end
Affected
Every phone behind SW-01
Carrier side
Clean
! collisions on the ports the phones use