911 Call Question

[kevin.hu]

Hi,

I have a 911 call question.  Let's say I am in Boston office but my voice gateway to the PSTN is in LA office thru my internal WAN.  This gateway has a PRI to the PSTN.  Is it possible to route my 911 call to the local Boston 911 call center thru that voice gateway in LA?

Thanks!

[George Thomas · Accepted solution]

You can but thats not desired and illegal. The callback number will not be correct and emergency services will show up in LA rather than Boston.

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[Jose Pablo Villalobos Urena · Accepted solution]

Kevin for 911, its mandatory to have a Local router.

Please Kudos/rate if this help!

[kevin.hu]

Jose,

If 911 regulation mandates a local router, how do big corporations consolidate voice gateways?  Unless it is only applicable for SIP trunking service and not traditional PRI connection.

Thanks

Kevin

[George Thomas]

Certain SIP providers route the call to the correct PSAP based on calling number. If the service provider doesn't support, companies usually buy analog lines for 911 calls. If the calls are not routed to the correct PSAP, 911 is not going to be of any help.


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[kevin.hu]

Thanks George.  I just did a little research and found this Emergency Routing Service (ERS).  So it is possible to centralize all call going out of one of two locations and 911 calls are routed to this ERS call center.  From there, they route the 911 call to appropriate PSAP.  So we have an option to do either ERS or like you said, analog line locally for 911 calls.

[Dennis Mink · Accepted solution]

I would still hope/assumes whoever picks up the phone at the 911 dispatch centre, would try to the the 3 mayday questions answered:

-where?

-what is the situation?

-what is required?

I mean, how else is calling an emergency number gonna work from a mobile?

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[afmmanicke · Accepted solution]

For cell phones (really any phone) calling 911 and the "Where" question - think of it more as "It's not where your from it's where your at."   Your cell call goes to the tower and the service provider knows where that tower is located.   Based on that info the SP sends the call to the correct selective router and the selective router sends the call to appropriate PSAP.   This process relies on older and older technology (but still valid) the closer it gets to the PSAP.   Several PSAPs still run on CAMA trunks which were used long ago to track long distance billing.

This can be a problem when SPs fail to move the ALI info when someone takes the land line with them when they move.  

Last point - If you're a large corporate customer you may be able to maintain your own ANI/ALI with a company like intrado (http://www.intrado.com/)

TONY

[kevin.hu]

Thanks you all for your input.  So to conclude, I have two options:

1.  Cisco way - analog card installed everywhere on the local router and order analog line(s) for 911 dialing

2.  Outsource E911 management to a centralized 911 call center such as intrado.com or AT&T, etc.

[Chris Deren]

Third option would be to implement your own SIP trunking with e911 support.

HTH,

Chris