Interesting reads. It appears like the fcc doesn't necessarily mandate the "method" of obtaining location, merely the timeline and accuracy requirements.

HowStuffWorks "Enhanced 911"

Wireless 911 Services

And if you're really interested - here's the 2000 filing for Sprint PCS, which includes a lot of detail regarding the assumptions on where calls might be placed from, results, prototype tech used for obtaining signal, and assumptions around vendors ability to provide equipment: http://fjallfoss.fcc.gov/ecfs/document/view?id=6512058793

And a followup 2002 status (these pdfs are REALLY in depth, but not overwhelming with jargon): http://fjallfoss.fcc.gov/ecfs/document/view?id=6513074739

More specifics on page 12-13 of the second document. It appears that that the tower-based location information is calculated on the network side, and not necessarily the handset. OF course this probably changes over time as tech changes...but remember the FCC mandate doesn't specify the tech...so it probably all varies by location/market/carrier/etc.

No idea where to find more current docs.

It's like a look back in time. in 2000 i had a totally crap flip phone.

Thanks for inspiring me to learn something (God I love the internet)

 

Okay so didn't even attempt answer your question, got lost in the minutia.

Turning off GPS in the phone will not impact emergency services. It should only impact any location-aware applications you might have on the device.

When you dial 911 the phone/network in combination knows what to do.

 

I've only had to call 911 from a cell phone a couple of times.

Both times, I had to describe my location so that they could figure out which department to send me to.

One of those times they transferred me back and forth 3 times between two departments because both said it was the others jurisdiction at my location.

Either way, I'm less than impressed with my experience calling 911 from a GPS enabled cell phone.

-SF