Understanding carrier networks, and your questions answered

Q: I was wondering if you can tell me the differences between WCDMA and CDMA. I'd like to get a Motorola MS600 Z Slider, but I hear it's currently available only in Korea on ST Telecom's network, which is WCDMA. Can I buy this phone and use it in the United States with either Verizon Wireless or Sprint'?
—Matthew

A: Deciphering the cell phone alphabet soup can get a bit complicated, but the easiest way to differentiate between the two technologies is to think about what they can do. WCDMA--which stands for Wideband CDMA--is a 3G technology built for broadband wireless data speeds, while CDMA is a 2G technology that offers slower data speeds (for more information, see CNET's quick guide to 3G). Now here's where it gets complicated. While you may think WCDMA is the natural outgrowth of CDMA, the two are incompatible. WCDMA borrows some of its technology from CDMA, but actually, WCDMA is the 3G technology that GSM carriers such as Cingular and T-Mobile are moving toward. That's because it borrows some of its standards from GSM as well. WCDMA, which is also referred to as UMTS, is backward compatible with GSM, so phones such as the Samsung SGH-ZX10 have such technologies.

Now, concerning the Motorola MS600, sadly, the answer to your question is no. It's a very sexy phone, but CDMA carriers Sprint and Verizon are using EV-DO, which is a different 3G technology. If you're really desperate to get it, though, I would wait if you can. Motorola is promising a U.S. version sometime this year.

Q: I am on an old AT&T Wireless contract with a Motorola V60t. A friend gave me their Motorola V220, but Cingular says I can't use it with my old AT&T service because that service is digital, while the V220 is GSM. Cingular said if I were on a GSM service from the beginning and not on digital, it would just swap out my phones. So it wants me to switch to one of its Cingular plans, which I don't want to do. I don't want to be forced to buy a new phone either. Any suggestions on how I can get this phone on my current AT&T contract?
—Becky

A: Cingular isn't telling you the whole truth on this one. First off, both TDMA and GSM are digital technologies. What's more, TDMA, which preceded GSM, is the technology on which GSM is based. So what Cingular should have told you is that you're using the wrong kind of digital technology to be fully compatible with its current network. Since the merger, Cingular has been phasing out TDMA, so your options for extensive nationwide coverage are dwindling. While it's too bad Cingular is blaming you for the problem (not the best customer service), you probably will have to sign a contract if you want to use the V220. As I said in last week's On Call, while Cingular isn't requiring most AT&T folks to adopt a new contract, cases such as yours are an exception. In the company's eyes, since you're migrating to new equipment and a new network, as well as using a SIM card for the first time (TDMA phones don't use SIMs), a contract is warranted. Thus, although you can avoid buying a new phone, a new contract looks inevitable.

Q: I use a Motorola Razr V3 with a prepaid Cingular account, but I'd like to switch to a normal monthly plan while keeping my number and my phone. Will I have to sign a contract, or can I just pick which plan I want and go month-to-month? Cingular told me I have to sign a contract. Is that true?
—Georgio

A: Unfortunately, Georgio, Cingular is correct in this case. Even though you've been with the carrier for some time on a prepaid plan, you will have to sign a contract if you want to move to monthly service. Now, this isn't the most consumer-friendly practice, but as I said last week, carriers always stick you with signing a contract when electing monthly service for the first time. And for you, it's doubly annoying. At least when you sign a new contract, you're entitled to rebates on a new phone purchase. But since you're using your same Razr V3, you won't get anything back. You can, however, still make it work for you in a way. If you can't convince Cingular to give you a break either by requiring only a one-year contract or by giving you a couple of months free, why not take one of the free phones it's currently offering? Right now, signing a contract entitles you to a free Nokia 6102. It's not a bad phone, and you can always save it for use at another time. Or you can sell it and make some cash.

Q: For the last two months, I have seen phone calls on my T-Mobile bill that I didn't make. This started in January with a total of 101 minutes, then again in February for a total of 192 minutes. I haven't gone over my anytime minutes yet, but I'm afraid if this continues, I may go over soon. I called T-Mobile to ask about these calls, and the company informed me it's almost impossible to hack into a cell phone. So if I'm not making these calls, who is?
—Dawn

A: My first reaction would be to suggest that T-Mobile is billing you incorrectly. After all, it wouldn't be the first time a carrier makes an error on a customer's statement. But if that's not the case, I thought of another possible reason. Back in the early 1990s when we used the chunky, analog phones, a controversial issue developed, called cell phone cloning. Using an electronics scanning device, someone could steal a cell phone's identity. They could then copy that identity to another handset and make calls that would be charged to the victim's account. Digital technologies such as CDMA and GSM have made cloning more difficult, but it's still theoretically possible.

All GSM phones (such as your T-Mobile handset) have an IMEI, which stands for International Mobile Equipment Identity. The IMEI is a 15-digit number that identifies a cell phone for use on a particular carrier's network (CDMA phones use an ESN, or Equipment Serial Number). When you turn on the phone or make a call, your phone sends the IMEI to your carrier's network to identify it and approve it for use. When you lose your phone, your carrier blacklists the IMEI, so even if a new SIM card is inserted, it will be useless. You can find your phone's IMEI by looking on or behind the battery, by looking at the box, or by typing *#06# on your keypad. GSM phones also use an IMSI, or International Mobile Subscriber Identity, to help the carrier identify a subscriber. But unlike the IMEI, which identifies your phone, the IMSI is attached to your SIM card and identifies you as a subscriber. So, if you put your SIM card in a new phone, you take your IMSI with you while you gain a new IMEI.

But enough gibberish--the reason I'm telling you all this is that a person would have to steal your IMEI and your IMSI to clone your phone. Although it's difficult, it's not impossible, as even T-Mobile said. I would suggest being firm with your carrier and insisting the calls were not made by you. If you want, you can complain to the FCC, or as a last resort, you can change your phone number.