Okay, I know that Cingular uses a 850MHZ GSM, but the phone that I have with them now also uses 1900MHZ (Moto T729). I bought a MPX200 unlocked the phone and installed the simcard, but I get "no service". Can this phone be used with Cingular or not. Also here a question, if Cingular pays AT&T out would the phone work then?

Thanks for the info
Glen

I think you're in a bad spot there. The MPx200 is listed as:

Motorola MPx200 (GSM/GPRS 1800/1900 MHz)

If you've unlocked the phone and you're using the Cingular SIM, then you just don't have 1800/1900Mhz service there.

If Cingular buys out AT&T who knows what would happen

I am going to piggyback on this thread, does anyone have Cingular's GPRS settings handy? Thank you!

most of cingular's network is 850 even though they show 1900 on a map. Usually what they are doing is using Tmobile 1900 until they get 850 towers in the area. After the 850 towers go up the intelligent roaming in the sim chip will not let the phone roam on a 1900 tower in your home area. If you live on the southern east coast, carolinas and south georgia, then cingular has 1900 band service. It really sucks, I have service with tmobile and cingular. My tmobile sim chip will work in both of my phones but the cingular sim will only work in the nokia with 850 band. Hopefully when cingular and attws get merged my mpx will work on cingular.