I have a mystery... here's the setup: Bria -> CallCentric -> 3CX -> Bria The first Bria (a softphone by CounterPath) calls sip:email@example.com which is the SIP URI of the second phone (which is an extension on the 3CX switch). The call completes fine. Then the second Bria puts the call on hold, and the 3CX switch starts playing hold music, which can be heard on the first Bria. 30 sec later the call drops. I searched the forums here, and the existing threads talk about silence detection settings on VOIP gateways, etc. I have no hardware involved, so the only way to fix this would be with a setting on the Bria softphone or the 3CX switch. I've crossposted to the Bria forum too.