Until asterisk decides to hang up…the lines remain tied up for over a minute (sometimes longer).
Its really apparent when an incoming call is sent to IVR or voice mail.
A call that is answered by a “live” person will hang up if the person on the asterisk side hangs up first but not if the caller hangs up first. (asterisk waits for over a minute or until the user on the asterisk side hangs up. this was done as a test. We don’t normally stay on the line after a customer hangs up.
and look at the sections for busydetect, busycount and callprogress. they may not apply to you/your telco, but that’s where to start. it’s also worth checking with them to make sure you’re getting loopstart. kewlstart would be better if available, then you can use a polarity reversal to signal call end.