Tips for calling 911 with a cell phone - A peek under the hood

[Jelf]

I am a software developer working with online maps and location technology.  Earlier this year I became interested in what happens when someone with a cell phone calls 911.  In particular I wanted to know the details of how the 911 dispatcher learns the *location* of the caller.  What kind of digital magic happens behind the scenes?  

Much of what I learned came from reviewing documents on the FCC’s website.  On one hand I learned that the FCC requires a wireless carrier handling a 911 call to produce coordinates for the caller’s location.  Sounds good, right?  On the other hand I learned that many carriers have exempted themselves from this requirement over large portions of the area they serve.  I also learned that the coordinate accuracy most of us easily get on our smartphones (or handheld GPS) is often 10 times more accurate - or more - than the coordinates produced by the wireless carrier handling a 911 call.  

Recently I finished a report that shares what I learned.  That report consists of:  
1.  A list of tips for calling 911 with a cell phone.  
2.  Background information so you understand the big picture.  
3.  Detailed information to support each tip.  
For those wishing to dig into the source material for themselves, the report includes links to various documents on the FCC website.  

I posted a copy of this report on my server at
https://mappingsupport.com/p/sar/call-911-with-a-cell-phone.pdf

Here are the tips.  I am happy to answer questions.

--- Tip #1 ---
If you need to call 911 and your cell phone shows ‘no service’, then you should call 911 anyway and let it ring 45-60 seconds before hanging up.

--- Tip #2 ---
You should give the 911 dispatcher your location by providing (1) a street address, or (2) a verbal description the dispatcher understands, or (3) your latitude longitude coordinates expressed as decimal degrees.

--- Tip #3 ---
FindMeSAR is a browser app that was developed as a public service specifically to provide an easy and ‘no cost’ way for anyone with a smartphone to display their coordinates and accuracy value while their phone is either online or offline.  This is not a commercial product of any kind.  It is a volunteer project just to try and help people when they need help.

--- Tip #4 ---
When you call 911 with a cell phone the wireless carrier handling the call might not produce *any* coordinates for your location.

--- Tip #5 ---
Even if the wireless carrier handling your 911 call does produce coordinates for your location, the coordinates you can obtain from your smartphone are either (1) more accurate or (2) a lot more accurate than the coordinates produced by the wireless carrier.

--- Tip #6 ---
If (1) your phone is not within range of a cell tower and (2) your phone does not have a current copy of the satellite ‘assistance’ data, then it will take 15 to 20 minutes before your phone will produce coordinates for your location.

--- Tip #7 ---
No one is monitoring the wireless carriers to see whether or not they are in compliance with the standards and requirements that the FCC has adopted regarding wireless calls to 911 and coordinate data for the caller’s location.

--- Tip #8 ---
If you have an android phone then to get the most accurate coordinates set the location mode (or method) to “GPS only”.

--- Tip #9 ---
If you have an Android phone then there is a free and easy way to find out if your phone can produce more accurate coordinates by using data from both the USA satellites (GPS) and the Russian satellites (GLONASS).

--- Tip #10 ---
Phones that have no service plan at all can still (1) call 911 and (2) run an app that displays coordinates and accuracy on the phone’s screen.

--- Tip #11 ---
If at all possible, make a voice call to 911 instead of texting.

--- Tip #12 ---
If you do text to 911, then the dispatcher is most likely not going to have *any* location data for you unless you include it in your text.

--- Tip #13  ---
After you contact 911 take steps to make your phone’s battery last as long as possible.

Joseph

[Nomad]

I'd be happy if folks knew the differance between east and west bound on the expressways  when calling , just because your on the " east side" of the city does not mean you're going east bound .

But that seems to advanced for many  callers .

[Core]

I'll admit I did kind of wonder exactly what happens.

[Jeremy K]

I wondered that a couple times ,I knew it wasn't anything like what they show on the make believe detective shows my wife watches.

[grampy]

Some good info! Thanks for sharing. 

[Nomad]

 I don't work,in the 911 center so take this win a grain of salt .Your call is answered by a call taker not a dispatcher , land lines addresses shows up on the screen , which in the old days was compared to,the one you gave  them to judge if it was a false call or not . 

With cell calls I've never heard a dispatcher say what location the call is coming from , only what tower it's hitting .

Now as you tell the call taker your info, they're entering it  into the system and sending it to poilce / fire / ems  dispatcher  . Some callers get mad because they keep asking questions not realizing , dispatch is already sending us . With luck any added info will be sent to me over the air or to my computer .

What you say is key to what gets sent and how fast, which is why for poilce calls , the caller often says, ' I think he has a gun", and for minor ems calls which would not bring a response , they always use the key words, " trouble breathing "

 

Smoke alarm going off in a building , nearest engine or truck. Smoke alarm with an odor of smoke or slight amount of smoke  , 1 engine 1 truck and a BC,  Smoke alarm with heavy smoke or fire, 3 engines 2 trucks 1 rescue and a couple Chiefs to mess everything up.

Cell phones of today are carried by everyone which means a call gets placed faster, it's also brought about a tremendous amount of false or " good intent " calls. Everyone wants to call , I can't tell you how many "car fires" I'm sent to that are over heated engines. Here's a hint, a car pulled over with a little bit of white " smoke "from the hood and a guy sitting in it is not a car fire .

Went for a " jumper" , woman in purple coat standing on Main st  overpass of  the RR tracks. Get there and it's  10 year old girl with a sled going up and down the hill next to bridge . 

A walker can't stop and look at the river bottom  from the Veterans bridge with out generating jumper calls. Went for one guy who had a giant camera and was taking photos.

This time of year we go,for house fires , when it's just the drier vent , everyone wants to,use that cell phone ....