[Asterisk-Users] 911 context, is this right?

[Adam Goryachev]

On Fri, 2005-06-03 at 08:28 -0600, Rich Adamson wrote:
> > I have 3 analog trunks zap/1, zap/4 and zap/5.  zap/5 is the least used
> > line.  Would the following work for 911 calls?
> > 
> > [e911]
> > exten => 911,1,ChanIsAvail(Zap/1)
> > exten => 911,2,Dial(Zap/1/911)
> > exten => 911,3,Hangup()
> > exten => 911,102,ChanIsAvail(Zap/4)   
> > exten => 911,103,Dial(Zap/4/911)
> > exten => 911,104,Hangup()
> > exten => 911,203,ChanIsAvail(Zap/5)
> > exten => 911,204,Dial(Zap/5/911)
> > exten => 911,205,Hangup()
> > exten => 911,304,SoftHangup(Zap/5-1)
> > exten => 911,305,Wait(2)
> > exten => 911,306,Goto(204)
> > 
> > Did I get the Priority + 101 idea right here?
> 
> In your example above, if ChanIsAvail(Zap/1) finds that Zap/1 is
> unavailable, then priority 102 will be executed. However, what do
> you want to happen if Zap/1 is available (at least from asterisk's
> perspective), but the pstn line on Zap/1 doesn't process the call
> for whatever reason?

One thing that bothers me with this style of dialplan for emergency
numbers... What happens if you already have a emergency call on zap/5 ??
You have disconnected one call to emergency in order to place a second
call, IMHO, that isn't a good thing to do :)

So, question is, how can you ID that zap/5 is *currently* involved in a
emergency call?

exten => 911,1,ChanIsAvail(Zap/1)
exten => 911,2,setgroup(911zap1)
exten => 911,3,Dial(Zap/1/911)
exten => 911,4,hangup
exten => 911,102,setgroup(911zap1)
exten => 911,103,checkgroup(1)
exten => 911,104,softhangup(Zap/1-1)
exten => 911,105,ringing ; Otherwise user might give up waiting and
panic
exten => 911,106,wait(2)
exten => 911,107,goto(1)
exten => 911,203,congestion

Anyone like to comment on something like that?? Obviously, it can be
extended to handle multiple lines, etc... and it should avoid
dis-connecting an existing 911 call. Note, you should check priority
numbers, and etc... this is just off the top of my head...

Regards,
Adam