911 multple-alert question

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Asterisk Users 6 Comments

Can you set up asterisk so when a 911 call is placed, in addition to the
call out to the PSAP, it also alerts multiple other phones on the switch
and will display detailed information. Such as alerting a receptionist
or security guard there is a 911 call elsewhere in the building and the
location of that call within the building? If so, how?

Thanks in advance for the help…

6 thoughts on - 911 multple-alert question

  • Here’s one example of non-AGI notification:

    exten => s,n,System(/usr/sbin/sendEmail -t carlos@televolve.com -f
    switch1@televolve.com -u “911 call was placed” -m “911 call from
    ${CDR(accountcode)} ${CALLERID(num)} – ${CALLERID(name)} via
    switch-1.televolve.com to ${911PROVIDER}.”)

    This of course requires the sendEmail program, which is hugely useful
    throughout our systems for many purposes.

  • Thanks for the response. You gave me some ideas I didn’t think of such
    as sending a text message to the on-call security person’s cell phone.
    However, while I know I can get the 911 call to call other phones, I
    also need location data. I know there are ways to do it, but I don’t
    have the kung-fu for things like databases, and am wondering if there’s
    something simple in Asterisk like a flat file used to correlate phone
    number and location. Then, there’s the part of how to get that
    additional data to display on a phone. To throw a wrench in it, I don’t
    want local security to answer, just to be alerted the call is going on
    so they can be the first on scene and make themselves available to
    direct emergency personnel when they arrive.

    Thanks Again!

  • 1) The Asterisk database? You can access it with dialplan applications.

    2) Set the location as a channel variable in sip.conf? (Keeps all of the
    ‘phone specific’ stuff in one place.

    Just being a bit paranoid, but fiddling with 911 calls always makes me
    nervous. I’d dial the ‘real’ 911 call over a copper pair first and then
    after (or in parallel) do all your kewl stuff.

    I’m sure there will be a lawyer somewhere out there just itching to sue
    when the ‘real’ 911 call doesn’t happen because of some minor FU on your

    What’s your legal exposure if your location data is wrong? I think I’d
    want a letter absolving me of liability signed by the CEO in my back

  • You’re absolutely correct. The 911 system maintenance is a PITA.

    Our current PBX routes all 911 calls to an box we call the “Proctor
    Box”. That box does a couple things. First, it assigns an ANI to a
    number. So for example, 3-digit extensions get a real 10-digit numbers
    assigned. It then routes that 911 call out a dedicated CAMA trunk to the
    PSAP. Additionally , we pay a third party company to upload our location
    data to the ALI database, so when our provided ANI hits the PSAP, they
    can pull proper location info out of the ALI database.

    The other thing this box does is feed a couple local display terminals.
    These terminals alarm and display local information from it’s own
    internal database during a 911 call for local security folks. In the
    meantime, I have the PBX itself which contains its own telephone
    directory with location and department information, and it’s own
    Emergency Services ID. It will use this ID if the CAMA trunks are out of
    service and the phone system decides to route the 911 call out a normal
    PRI. This data we try to use as a baseline for the 911 data. So we
    currently have multiple databases I have to keep 100% in sync, with a
    1000+ set campus with people moving constantly amongst the 25+
    buildings. It’s a nightmare.

    Basically, as we migrate to Asterisk, I need to figure out if I can
    replicate our current functionality. The preference is to come up with
    something much nicer than a half-dozen data points that are never in
    synch. If I can’t find a solution in Asterisk, then I’m stuck using
    something like we already have.

    …and yes, as you have imagined, there have been a few FUs in the past.
    We’ve dodged a number of bullets. I’m hoping I can resolve this when we

    I will look into the local channel variable in the sip.conf. That sounds
    promising. If I populate that data, how does it make it to the display
    of a phone on campus? I guess that’s a piece I haven’t either read or
    been able to wrap my head around yet.


  • sip.conf:

    setvar = LOCATION=Main Lobby


    exten = *,n, set(CALLERID(name)=Tora! Tora! Tora!)
    exten = *,n, set(CALLERID(num)=${LOCATION})
    exten = *,n, dial(sip/security)
    exten = *,n, hangup()

    This shows ‘Tora! Tora! Tora!’ as line 1 and ‘Main Lobby’ on my cisco

  • Thanks a million for the examples. I’m going to try it out in my test
    environment over the next couple weeks and see what happens!