SIP trunks and Message.com calls
Understand the difference between telephone signaling, audio and the application call state.
What a SIP trunk does
A SIP trunk connects a phone system to a telephone provider. Signaling establishes and ends the call; the audio travels on a separate media path. A connected call indicator alone does not prove that audio works in both directions.
The call path
An incoming call reaches the assigned number through the carrier and is routed by the phone system. Message.com applies the configured greeting, menu, AI and queue behavior. A browser or desk phone receives the call through the selected answering path.
Application events are separate
Do not model the integration as a carrier posting a simple ringing webhook for every SIP INVITE. The voice services reconcile carrier, bridge and room events with the Inbox conversation. Use the documented call APIs and supported events for your integration rather than sending synthetic carrier events.
Diagnose signaling and audio separately
For a quality issue, record the call ID, time, devices, direction and symptoms. Compare a browser call and a desk-phone call using the same destination. Delay, packet loss, codec conversion, device processing and the destination network can each affect the result.
Test the complete lifecycle
Check inbound and outbound audio, ringing, hold, transfer, voicemail and hangup from both ends. Confirm that a finished call disappears from the active queue and appears in history. An API success response is only one part of that test.