[Asterisk-Users] 911/Emergency calls + Caller ID

[John Todd]

I'm not sure I can parse your examples correctly.  I'm not being 
snide, but do you use Asterisk on a regular basis?  Do you understand 
how applications work, and how call handoff is done between Asterisk 
servers?  Your example doesn't seem to make sense, no matter how I 
think about it.

Of course, the problem with 911 is the problem of location of the 
originating handset.  That much has been clear for years.  Getting 
that information to the 911 call center is the problem; it's pretty 
much worthless info even if you have it inside the PBX - you could 
just as easily have an external database that maps extensions to 
locations - why bother with the PBX if there is no in-band signalling 
to the PSAP?

This makes me think a bit about some other 911 ideas I had a while 
back, using lat/lon/altitude.  Can ADSI tones be transmitted through 
"any" phone call on the PSTN?  It might be interesting for PBX 
systems to pass across the lat/lon/altitude of callers via ADSI 
in-band.  This will never work, of course, since nobody would trust 
the transmitters.  The 911 question almost instantly spins into a 
political issue, and not a technical issue, since there are a number 
of clever ways to solve the problem but not a number of clever ways 
to bang solutions into people's heads.

Bumping calls to clear a path for 911 is possible within Asterisk 
already - see the "SoftHangup" application.

JT


>Problem: 911 calls placed through Asterisk are associated with the 
>physical location of where the CO trunks terminate. This is not 
>really a problem when all extensions are located in the same 
>building, but when Asterisk is used in a campus-like or otherwise 
>networked environment, it can get messy.
>
>A common solution is to install a few analog lines at each location, 
>for emergency calls only. But by making clever use of Caller ID (and 
>adding a 'location' field to extensions.conf), it should be possible 
>to  properly identify the location of the caller:
>
>exten => 1001,1,John Doe,1223 Bell Ave. Room 51
>
>For this to work, you would have to be able to apply rules to the 
>911 context in a dial plan, to replace the *name* portion with the 
>*location* portion.
>
>A similar rule could be defined to drop other calls if 911 is dialed 
>and all lines are busy (e.g. drop the lobby phone but not the front 
>desk, or drop local vs. long distance, caller ID calls vs. 
>non-identified calls, etc.).
>
>Getting lengthy, better stop.
>
>Dylan.