[Asterisk-Users] Asterisk connecting to a proprietry PBX

[Dave Fullerton]

Gonzalo Servat wrote:
> Hi guys,
> 
> I'm interconnecting an Asterisk box with a Lucent Definity PBX by
> means of FXO/FXS ports on a TDM2400 card. Everything works well,
> except for one little thing. Every now and then somebody (from an
> Asterisk extension) will call another extension on the Lucent Definity
> PBX and they hit their voicemail. They caller leaves their message (or
> not) and hangup, BUT the Lucent sometimes doesn't detect the hangup
> and the channel never gets dropped. The call goes on and on and on (I
> often have calls hanged for 20 hours or more). The problem is that
> with the limited FXO/FXS ports we have, I often have people complain
> they can't dial somebody, but it's simply because there are hanged
> channels.
> 
> I did a ChanSpy on the hanged channels and all there is is dead
> silence. I guess Asterisk is not going to drop the channel until it
> hears the busy pattern, which I guess makes sense as you wouldn't want
> to be hanged up on if there is any silence (obviously).  I was
> wondering if there is some way I can configure Asterisk to hang up
> calls if there is more than X minutes silence in a channel. For now, I
> think the quick (and dirty, and not very nice) solution is to set an
> AbsoluteTimeout of 1 hour on the calls, as 95% of calls are less than
> one hour and will ensure there are no hanged chans longer than 1 hour
> in the system.
> 
> Another idea I had in mind is to, maybe, set the voicemail system
> (Audix) to cut messages after X minutes. I don't know for sure if the
> (Asterisk) caller is leaving a message or not, as most voicemail
> systems have a message size limit and drop the call anyway. Strange,
> huh?
> 
> Any suggestions? opinions? sympathizing words? :-)
> 
> Thanks in advance guys.
> 
> Cheers,
> Gonzalo

I have also had similar problems, except I'm using sipura 3k boxes. The 
FXO port on the sipura is connected to a station port on our PBX. Now 
and then, a user hangs up on the PBX and the sipura detects the hangup 
but asterisk doesn't "hangup" the sip channel. The sipura shows that it 
is on-hook and idle via the web page. The other end of the call has no 
means of knowing if the call is still active or not so it all has to be 
done on the PBX side.

My band-aid solution was to limit each call to one hour in the dial app 
(almost all calls are only a few minutes). Then if I don't notice the 
zombie call it will only be there for a relatively short time.


-Dave