Who knows how it would work on Cingular or even on Verizon. Neither company will let you activate an AMPS (analog) only phone any longer. cingular won't even let you activate new TDMA (IS-136) service since cingular wants everyone on the GSM network now. People who are still on the TDMA network can stay there although Cingular has been taking more and more resources from their TDMA side and putting them into the GSM side so reception in some areas has become quite iffy. If you had service with AT&T Wireless or Verizon Wireless with just analog they'll likely let you keep it. They won't activate anything other than recent technology and even Verizon won't let you activate any new phone that is not GPS equipped. The only way you could possibly use it is as an emergency phone to dial 911 only since it's mandated that
911 should work from all phones regardless of whether they are registered on a network.