I have been having this problem in FXO with asterisk that after call hangup from the far end but it does not hangup from the asterisk server end resulting channel block .
Well i have done with busy detect . But exactly what will be the rite scenario to catch the hangup signal ?
You need disconnect supervision from your network operator and you need Asterisk configured to match the type of disconnect supervision used. US providers tend to use a short period of no battery, whereas the UK uses a reversal of the A and B wires. I believe some South American ones put a busy tone on, but do not use any out of band signalling. In incoming calls.
Domestic lines may well not have any out of band supervision.
Supervision on FXO lines is sent on the Release event. For outgoing calls to landlines, this is often several minutes after the hangup event, to allow the callee to re-answer on a different phone, on the same line. This probably varies between network operators.
Another prob i find is that call is hangup but again it comes to the agents …and when agent receives hears call disconnect tone.I guess this is also related with hangup signalling from the network side . Isnt it?