ConfBridge doesn't decrease the number of users in conf

I’ve set up some extensions for ConfBridge. Here’s my bit of code:

exten => _30N,1,Log(NOTICE, "Entering conference bridge") exten => _30N,n,Answer() exten => _30N,n,Set(CHANNEL(musicclass)=default) exten => _30N,n,Set(CHANNEL(language)=en) exten => _30N,n,Set(CONFBRIDGE_JOIN_SOUND=en/conf-hasjoin) exten => _30N,n,Set(CONFBRIDGE_LEAVE_SOUND=en/conf-hasleft) exten => _30N,n,Wait(1) exten => _30N,n,Authenticate(1234) exten => _30N,n,ConfBridge(${EXTEN},Mcs) exten => _30N,n,Wait(1) exten => _30N,n,Hangup()

This lets me enter conferences, but somehow, after I hang up, it doesn’t realize that a user has been disconnected, so the next time someone calls, it says, “there is one user in conference”, and then two, and so on.

Any ideas on this? I’m new to setting up conferences. It seems like a great system except for that problem.

Also, I used the CONFBRIDGE_JOIN_SOUND and CONFBRIDGE_LEAVE_SOUND as “conf-hasjoin” / “conf-hasleft”. Users will understand what it means but it would be a lot better if it’s the beep-beep (low-high) sound that most other conferences use, and then it should play the high-low beep-beep on exit. But I couldn’t find those sounds anywhere.

Thanks for any advice on this. This is all on Asterisk 1.6.2.7-1ubuntu1.1

What device technology?

If relevant, what form of disconnect supervision?

Is this, by any chance, actually an outgoing analogue line call?

These are regular snom phones (870s). Is there anything else I need to do on them?

Thanks

SIP technology, then?

Yes, plain old SIP.