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

[Andrew Kohlsmith]

On Friday 03 June 2005 05:50, Chris Coulthurst 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)

Why would you do this?  Use a group:

zaptel.conf:
group = 9
channel => 1,4,5

[e911]
exten => 911,1,Dial(Zap/g9/ww911)
exten => 911,102,SoftHangup(Zap/5)
exten => 911,103,Goto(1)

Basically dial using the first free line in group 9.  If the Dial fails, hang 
up zap/5 and try again.  I added two 'w's in the dial string just to make 
sure the telco switch is ready to receive DTMF (this may not be necessary)

I'm not checking other lines than 5 (there's an assumption that line 5 is 
always going to work but in an emergency situation I'd just as soon soft 
hangup all 3 channels and try again.  

I also *TOTALLY* disagree with using Ringing() to calm the caller.  If the 
call's not going through they SHOULD be thinking of using an alternative way 
to reach 911, not calmly waiting for an answer that just wont come.

-A.