<http://www.911dispatch.com/911_file/tech_choices.html>

  Phase II Wireless E911 Technology Choices
 
  As of May 2003, here are the methods being used by the largest wireless
  carriers to provide Phase II service:
 
  Carrier Network
  Technology Phase II Technology Type
  T-Mobile GSM E-OTD* network
  Nextel iDEN A-GPS handset
  Cingular TDMA-GSM E-OTD* network
  AT&T Wireless TDMA-GSM E-OTD* network
  Verizon CDMA A-GPS/AFLT handset
  Sprint CDMA A-GPS/AFLT handset
 
  Both Cingular and AT&T Wireless are phasing out their TDMA networks.
 
  * In Oct. 2002 Cingular and AT&T Wireless notified the FCC that it was
  halting E-OTD development because they were uncertaint that
  the technique could meet the accuracy requirement by the Commission's
  deadline. In March 2003 T-Mobile also told the FCC
  it would stop deployment of E-OTD gear. The carriers said they would test
  U-TDOA technology to provide Phase II service.

<http://www.phonescoop.com/news/item.php?n=404>

  Cingular Switches to U-TDOA for E-911 Positioning    
 
  Date Posted: Dec 17, 2002, 12:25 AM Source: Wireless Week

  Cingular has decided to switch technologies for meeting the FCC's
  E-911 mandate for locating 911 callers. Cingular has told the FCC
  that after completing successful field trials involving
  TruePosition's network-based U-TDOA technology, it was moving away
  from E-OTD, which so far has failed accuracy tests, resulting in
  delays and financial penalties. Cingular in October suspended
  shipments of E-OTD gear and began testing TruePosition's solution.

<http://www.trueposition.com/news_03.10.03_cingulargsm.php>

  TruePosition and Cingular Sign National Multi-Year Agreement For GSM
  Location Solution

  TruePosition's U-TDOA Location Solution Provides High Accuracy For
  Anyphone, Anywhere

  KING OF PRUSSIA, Pa. and ATLANTA, Ga., March 10, 2003