the scenario is
inbound calls are forwarded to external number, the trunk lines are not getting released even after the answered person disconnects the call
Assuming the outgoing lines are analogue lines, this is expected behaviour for calls to the PSTN. The time between hangup and network initiate release can be up to 3 minutes, although, in most places in the UK BT have reduced this to a few seconds within the last year.
The reason it is done is to allow the callee to hang up on one phone and pick up on another, phone without losing the call.
ISDN distinguishes between the CLEAR form the subscriber and the RELEASE from the network, but some SIP gateways treat CLEAR as hold, and some may ignore it.
thank you so much your great support
the thing is All lines are PSTN lines
this is the settings on Chanel_dahdi.conf
rxwink=300 ; Atlas seems to use long (250ms) winks
i have tried uncomment busydetect also but getting the same issue
I hope you understood
Not all PSTN operators signal disconnect and those that do don’t do so on all lines (out of the way places may have unusual exchanges).
They will not signal disconnect until they receive an ISDN RELEASE. If the called party is on an analogue line, RELEASE may not be signalled until up to three minutes after they clear (in some cases there may be no called party clearing at all).
In the UK, a delay of several minutes was common until early this year, but most lines now generate RELEASE a few seconds after hangup. The change was made because few people have extensions in parallel. Most use cordless, instead.
Almost certainly everything is working as intended, and if any change can be made without moving to ISDN, or an ITSP who connects through ISDN, you will need to see if the telephone operator offers a special business line service that supports remote called party clearing.
I really appreciate your support
in this case when i enable busydetect and busy count pstn lines are getting released when the called or callee disconnects the call, but at that time the issue is when we are making outbound calls after the busycount time the call disconnects.
so either lines are hung or calls get dropped
if you can find any solution it could be so helpful