[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?
> > Why would you do this?  Use a group:
> 
> Yes, use a group... but...
> 
> > 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)
> 
> Boom, you just hungup on the emergency call that was already in
> progress.... I wouldn't call that even close to ideal. PS, you might at
> least somehow randomise the line you will hangup on...
> 
> > 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)
> 
> This will delay the call being sent, with absolutely no feedback to the
> caller.
> 
> > 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.  
> 
> Yes, line 5 may not work, and also line 5 is more likely to have another
> emergency call in progress. I disagree with hanging up channels in this
> manner... IMHO, it is worse to hangup an emergency call in-progress than
> to simply return congestion.... You must check that the call in progress
> isn't itself an emergency call.
> 
> > 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.
> 
> But the call *IS* going through, I just allowed the caller to hear
> ringing for 2 seconds instead of dead-air. We just made a line available
> for him, so what makes you think it won't go through? (OK, someone else
> might steal the line while we are waiting...). Of course, after the two
> seconds, if the line is busy, they will hear busy, and then be able to
> decide the best course of action.... Perhaps retry, etc...
> 
> In any case, whether you use a group, or play ringing, or don't, etc...
> IMHO, is irrelevant, what all of these dialplans are missing is the
> importance of NOT disconnecting an emergency call which is in-progress.
> 
> Of course, that is just my 0.02c worth...

Never did answer whether this effort is focused on a home system or on
a small business. It does make a difference.

If you are insistent on doing the above, then at least consider giving
the second 911 caller a recorded message that says a "911 call is in
progress" instead of arbitrarily dumping _any_ calls.

Assuming a reasonable size fire in a business, you're almost guaranteed
to have multiple 911 calls originating from employees that don't have
a clue that other calls are already in progress. By using the call 
dumping approach, you couldn't possibly program a resonable dialplan
that takes every assumption into consideration, regardless of how you
program it.

Murphy's law also says your system/dialplan will fail at the most
inopportune time. Therefore, if you don't have an alternative plan (that
does not rely on *), we'll watch for your case to show up in the court
records.

/* end of comments on this thread for me */