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

Dylan VanHerpen dylan at packetbell.com
Mon Jun 23 18:36:45 MST 2003


Now that I reed it back, I can barely make sense of it myself! Anyway, I 
was just thinking out loud, the example wasn't meant to be parsed. 
Asterisk would need some lower level changes to parse the extra field 
holding the location information, and to apply the routing rules to 
substitute the Caller ID name for the location. I was hoping this would 
be thought provoking for somebody smarter than me :)

 > Bumping calls to clear a path for 911 is possible within Asterisk 
already - see the "SoftHangup" application.
That sounds good, but what can trigger the SoftHangup app to drop other 
calls automatically when 911 is dialed?

Thanks, Dylan.

John Todd wrote:

> 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.
>
>
> _______________________________________________
> Asterisk-Users mailing list
> Asterisk-Users at lists.digium.com
> http://lists.digium.com/mailman/listinfo/asterisk-users
>





More information about the asterisk-users mailing list