phone fun, was GeoIP database issues and the real world consequences

Peter Beckman beckman at
Thu Apr 14 03:54:48 UTC 2016

On Wed, 13 Apr 2016, Jay Hennigan wrote:

> On 4/13/16 4:28 PM, Larry Sheldon wrote:
>> I am in frequent contact by a person that has a 917 NNX-XXXX-numbered
>> telephone who spends a lot of time with a person that has a 408
>> NNX-XXXX-numbered telephone, and they both live in Metropolitan Boston
> When either of those people dial 9-1-1, where does the ambulance show up?

  I suspect your response was sarcastic, but when you dig into what really
  happens, it's not nearly as sophisticated as one might hope.

  If the numbers are land or VoIP lines, and the address associated with the
  numbers are registered with the Automatic Location Information (ALI)
  database run by ILECs or 3rd parties to fetch the address keyed on the
  calling number, and the 911 PSAP is E911 capable, they operator will see
  the ALI address.

  If they are mobile devices, it depends. Basic gives you nothing (all phones
  since 2003 should have GPS, but people hang on to phones a long time..);
  Phase I Enhanced gives you the location of the cell site/tower, Phase II
  gives you lat/lon within 50 to 300 meters within 6 minutes of a request by
  the PSAP. Yep, the PSAP has to make a request for the phone location to
  the carrier, in which they have 6 minutes to reply. I assume this is or
  can be automated.

  After 6 minutes, you could be a long way away from where you started the

  If the phone numbers are not in the ALI, or are not wireless, or the PSAP
  (Public Safety Answering Point, the 911 office) is not set up for e911,
  they probably get nothing, relying solely on the caller to provide
  location information.

Peter Beckman                                                  Internet Guy
beckman at                       

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