asterisk users - Mar 2005 - Routing 911 calls

Has anyone used asterisk as a simple voip server? (I'm sure its been/ing
done).
If so... how did you provide 911 service?   Did you setup different
contexts and put sip phones in those contexts per county?

Also, is it possible to put a phone into multiple contexts?

For instance:

context=from-internal

Can I add a second context like with a , comma?  So the phone can have
the rules from 2 contexts?  How would I do that?

You really need an outside company to implement e911 for you. Your idea
of putting each phone in a separate context might work if;

You have a local emergency number for every caller in your dial plan.

You have maps that show the jurisdiction of every 911 dispatcher in your
service area.

You confirm the numbers on a case by case basis.

Every agency you deal with as a local number for emergencies.

The bottom line is that every number you assign to subscribers still has
to have a record in the PSAP database for address information to be
transmitted, so you will still need a relationship with a PSAP data
manager.

Bottom line, too complex and too much liability, you need outside help.
This is a huge issue right now and companies like intrado
(www.intrado.com) are working on it.

Find out who manages the PSAP database for your intended service area
and contact them to see if they have a VoIP e911 service available.

This issue also impacts cellular systems, but it is easier because each
cell site typically only covers one or two jurisdictions, in which case
the caller gets "close enough" to the right agency based on the cell
site they are connected to and due to the mobile nature of the systems
address information is not expected to be transmitted.

Newer solutions for cellular include GPS location information in the
call. The handset receives GPS info and distance info from each cell
site it can "hear". Simple math on the handset adjusts the GPS
location
based on triangulation of the last three known GPS coords (cell sites)

 
> -----Original Message-----
> From: asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-
> bounces@lists.digium.com] On Behalf Of Matt
> Sent: Saturday, March 19, 2005 9:02 AM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: [Asterisk-Users] Routing 911 calls
> 
> Has anyone used asterisk as a simple voip server? (I'm sure its
been/ing
> done).
> If so... how did you provide 911 service?   Did you setup different
> contexts and put sip phones in those contexts per county?
> 
> Also, is it possible to put a phone into multiple contexts?
> 
> For instance:
> 
> context=from-internal
> 
> Can I add a second context like with a , comma?  So the phone can have
> the rules from 2 contexts?  How would I do that?
> _______________________________________________
> Asterisk-Users mailing list
> Asterisk-Users@lists.digium.com
> http://lists.digium.com/mailman/listinfo/asterisk-users
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-users

Matt wrote:
>Has anyone used asterisk as a simple voip server? (I'm sure its been/ing
done).
>If so... how did you provide 911 service?   Did you setup different
>contexts and put sip phones in those contexts per county?
>  
>
I think that's what you'd have to do.
>Also, is it possible to put a phone into multiple contexts?
>
>For instance:
>
>context=from-internal
>  
>
Dunno... this'll work though:

context=from-internal-and-somethingelse

and in your extensions.conf

[from-internal-and-somethingelse]
include => from-internal
include => somethingelse

BTW, I think the best way to manage your * config files is to have a 
database of users,  and build your sip.conf, extensions.conf, etc from 
the database using a template language such as the template toolkit (Perl)

Cheers,
Jean-Michel.