Originally Posted by tkirane
it provides location information and personal info to the dispatcher when you call 911.
Just to be 100% technically correct I wanted to clarify a few things. The FCC has mandated location services ON THE CARRIERS, not the devices.
Also, the phone itself transmits nothing other than your caller ID to the E911 center. The center then references the a unique record in the MSO database for that particular call, and the response record includes longitude and latitude information, as well as the name and number of the account holder.
I just wanted to be clear that 'personal information' is NEVER sent from any device to E911 centers, nor are they even capable of recieving any other information other than a phone number that they then perform a manual lookup on that is out of band to the E911 call on a dedicated data circuit for these types of lookups.
Phones are located in 2 ways, GPS and Radio Triangulation. The Bullseye typically indicates the GPS option is turned on, which is much more accurate than triangulation, but neither is reliable indoors due to the structures interference with the signal.
Some links you may find helpful are:
Google KNOL on How Cellular E911 Works
Cellular E911 Location Discovery - a knol by Mark Fletcher
How E911 Works
My Weekly E911 Podcast RSS Feed URL:
E911 Talk PodCast
Avaya E911 Product Manager