[Asterisk-Users] HELP: How to detect a hangup tone?

[Charles Wang]

Dear ALL:

My scenario is:
SIP UA ==> SIP Proxy ==> Asterisk ==> CISCO 5300 trunk ==> PSTN
I make a call from SIP UA to a PSTN phone number, and SIP UA hangup first.
My Asterisk can receieve a BYE message, so this connection will be hangup.

But if my PSTN side hangup first, my CISCO will send BYE to Asterisk
after 30 seconds. And Asterisk disconnects this connection at this
time(receives a "BYE" via CISCO).

Does anyone have solution/idea to make asterisk hangup immediately?
How to change the configuration of CISCO and send a BYE immediately or
Asterisk can detect a hangup tone?

-- 

Best Regards
Charles