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

[Rich Adamson]

> > > 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...

That's all getting pretty messy, but you could stuff a value using
DBput when a 911 call is made, and clear the value at the end of
that call. Then on subsequent calls, use DBget to see if a 911
call is in progress.

But as mentioned previously, you've made a large number of assumptions
to even think you can place a 911 call this way.

You could probably do something like that with an AGI script, and
have a fair amount more intelligence in the decision tree.

If I recall correctly, seems like someone was taking about adding
global variables into asterisk, but I don't recall how global those
might be (if they are even there right now). That might also be a
way to track number of outstanding 911 calls.