Cingular told me that I couldn't just go on the internet or to a store such as Best Buy and buy a Motorola V600 or Sony Ericsson T637 {which would be cheaper} to use with their prepaid service. They said I had to get it from Cingular because of some chip they put in there. Is that true??
I don't know for sure but I would guess not. You need a phone compatible with the "system". Check it out at local "retail" stores Car Toys, Best, Radio Shack etc and get their view point. I got my phone from Version because it was $100 cheaper than Radio Shack etc. I have to say I am not happy with my phone or my provider and may change despite the cost. Call around and get more info. This is a good place to start. I think that the person you were talking to was blowing smoke up your "posterior".
Not exactly. You can buy any phone "locked" into Cingular...so, if someone is selling a T637 that they bought from Cingular or one of thier marketers it will work. Also, many Ebay folks sell phones that have been "unlocked" and will work with any provider that uses the frequencies for that phone. You will have to put a SIM chip in the phone. But if you have an unlocked or previous Cingular phone it will work with their SIM chip. Consider looking at a web site like Intelinetwireless.com to see what kind of deals are out there.
My own strong recommendation is go with a service provider that lets you use pretty much any GSM phone, does not lock it to their network, and does not cripple features in the phone. For Verizon specifically, ask what features they disable... I bought my phones from an Internet seller in New York, based on the phone features I wanted. I signed up with T-Mobile because they would let me use my own phones, do not lock them, and don't cripple them. I also got activation discounts. For the SE610, I also got the T-Mobile SE rebate. So far, I am very happy with the service, and the Nokia 6230 is a treat in the Prius. Robert
Verizon aren't GSM, so avoid them regardless. Verizon, Sprint and Nextel use their own unique proprietary networks; everyone else is GSM--and by "everyone else" I mean almost every country in the world, as well as US carriers including T-Mobile, Cingular and AT&T. I'm considering switching from T-Mobile to Cingular. If I do, I'll be able to keep my (unlocked) T68i and just put the Singular SIM card in it.
GSM technology used worldwide is not compatible with GSM technology used in the US. sprint uses CDMA just like verizon. Nextel uses GSM like cingular and att but also uses TDMA which is fading technology that no longer is effective because of the high volume of traffic experienced at most cell towers. cingular cellphones unlike most others uses a memory card to program the ESN (electronic serial number). the ESN is required by the FCC in order to determine who is making the call. each call transmits its ESN, MTN and # being called. the cell tower uses the ESN to determine what company issued the service so it can charge the appropriate amount (roaming if applicable, or long distance, etc) because of LNP (local number portability) started in 2002, one can no longer determine the carrier by the MTN alone. (mobile telephone number) with some phones that can be programmed OTA (over the air) ESN's can be changed. sprint to verizon and cingular to att and vice versa are possible with some handsets. you cannot change to different signal technology however. for those of you that are into computers, you can look at ESN's as being similiar to MAC's for network cards. the first 3 numbers (or 2 if in hex) designates the manufacturer of the phone.
The GSM technology is the same worldwide; however, different frequencies are used in Europe and elsewhere. A three or four band GSM phone will work just about anywhere in the world with the exception of Japan. Nextel uses a propriety system, iDen, which is TDMA based. It does not use GSM. All GSM phones, worldwide, use a SIM chip to store the phone's electronic identity and phone book. You can switch a phone's number and carrier, if the phone is unlocked, by simply putting in a new SIM card. You can find out a lot more on cell phones at Phone Scoop.