GSM vs CDMA coverage

[hsharma]

Folks..sorry for dumb question..in GSM networks, having T-Mobile service, I can see AT&T and/or Cingular on my Treo whenever I am in non-T-mobile area because they all use GSM. Is the same true with Verizon and Sprint and nextel (do they all use CDMA?) or does it depend upon whether the service providers have cross-roaming agreements!!
Thanks

[Janak Parekh]

It is also true between Verizon and Sprint, as they both use CDMA, as well as some smaller providers. You do need the provider roaming agreements to make calls without an additional cost. Verizon and Sprint do have a few in the US.

(Oh, and Nextel is not CDMA -- it's iDEN, which is a proprietary Motorola protocol.)

--janak

[frankenbike]

Verizon appears to have coverage that Sprint does not. Sprint does not seem to have CDMA coverage in areas where Verizon does, even for roaming.