What The Public Wants

Public Safety

An individual that calls 9-1-1 has two basic expectations:

  1. My  call will be answered by the correct 9-1-1 center
  2. The person answering my 9-1-1 call will know my location


call flow

We need to route wireless 9-1-1 calls by the location of the CALLER, not the location of the CELL TOWER they are connected to… If you look at the diagram above, we see that traditionally the LAST item the 9-1-1 call taker receives is the caller location. Too many times the call needs to be transferred to another jurisdiction. As depicted in the example below, the 9-1-1 caller will be routed to the wrong center.

Every month, we transfer thousands of 9-1-1 calls that are sent to the wrong center because of the current cell tower routing model.

Here is a local TV station in Atlanta report

Cell Sector

Here is a LINK to the FCC Chairman discussing this issue

We need to have the callers location calculated earlier in the process.

2018 :

  • Google  and Apple both began providing enhanced handset location information to the wireless carriers (and RapidSoS).
  • CTIA announces that the wireless carriers will provided better caller location to 9-1-1 centers

The Fix:

  • NextGen 9-1-1 includes the concept of using GIS to route the calls. When wireless carriers transition to ‘location based routing’,  wireless calls that are able to provide a location quick enough (within a few seconds) can be routed to the correct 9-1-1 center using GIS.

The Workaround:

  • Vendors are discussing possible options with their NextGen ESInet/CoreServices offering, they will ‘hold the call (for a few seconds) to determine if a good location arrives with the call – if so, they will use this location and GIS to route the 9-1-1 call . The backup will be to route the call by cell tower.
  • We are seeing location (phase2) arriving very quick these days, so this strategy may be a good short term solution.

The Google Android and Apple IoS teams (thank you) have stepped up to provide enhanced  9-1-1 location data. We look forward to the wireless carriers addressing this critical issue- we know they are working on it…

4 thoughts on “What The Public Wants

  1. Daryl Branson - DORA

    This is a nice, succinct description of the difference between MSAG-based wireless 911 call routing and geospatial wireless 911 call routing.


  2. Don Mitchell

    Routing by Location will greatly aid public safety. Finally. I applaud Motorola’s strategy and all the work done by the RapidSOS and ELS/HELO teams at Google/Apple.
    Long time coming.
    I remember testing routing by location back in 1998 (test systems) using Greyson Wireless. And some similar route delay techniques in service with Norm Forshee at St. Clair County waay back there. Thanks for keeping this topic in front of us.


  3. @Fletch911

    Another point to consider is the call setup time. As soon as you implicate the ‘D’ word (delay) people will freak out. But in today’s analog-based legacy world, there is a significant delay in call setup time, as the DTMF tones have to be passed between systems, Modern SIP-based networks will use IP protocols, transmitting the data faster and more efficiently. That being said, a few extra seconds in the core whuiekNGCS collec ting and verifying HI B


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