Since last fall, cell-phone users have been able, with some patience, to take their phone numbers with them when they change carriers. But it's still tricky to move a cell phone itself from one service to the next -- even when both carriers use the same wireless standard.
That's the case with most new phones provided by AT&T Wireless, Cingular and T-Mobile. All employ a technology called GSM (short for Global System for Mobile communications) that -- unlike the other standards supported by multiple nationwide carriers in the United States, CDMA and TDMA -- permits a seamless swapping of phones between services.
All a user would have to do is open the phone's case to swap out the thumbnail-sized SIM (subscriber identity module) card issued by the first company and pop in a new one.
And since GSM is the standard throughout much of the world, frequent international fliers could buy SIM cards with prepaid service for overseas calls to avoid steep roaming rates.
But those three domestic GSM carriers don't allow these options: They lock the phones they sell to prevent customers from swapping in another service's SIM card, then often decline to provide the unlocking codes a user would need to free its SIM slot.
By contrast, consumers in Europe and elsewhere generally can choose between buying a cheaper locked phone or a more expensive, unlocked version -- although the difference can amount to $200 or more.
Carriers say they have to do this to make sure they recoup the subsidy they provide to keep phone prices low. But in some cases, a phone will stay locked even after the carrier would have recovered that subsidy in the form of monthly service fees.
AT&T Wireless does not tell customers how to unlock their phones, although that procedure normally requires just entering the right code on a phone keypad. "We subsidize the phone and want to make our money back," said Ritch Blasi, a spokesman for the company.
Cingular will provide a phone's unlocking code to a user's new carrier only if the user switches services after a Cingular contract has expired. T-Mobile, on the other hand, will provide customers with unlocking codes after they've subscribed for 90 days.
This behavior has some people riled up, and some of those people are lawyers. New York attorney Scott Bursor has filed class-action suits against wireless carriers to challenge the practice, on the grounds that it amounts to monopolistic behavior.
"This is just an artificial barrier to changing carriers that is used by the carriers to lock people in," he said. "It's as if the power company said, 'We won't sell you electricity if you don't buy your refrigerator from us.' "
Consumers Union finds the practice of locking phones objectionable, but also still largely unknown to most users. "Not a lot of people know that it's even possible," said Chris Murray, the organization's Internet and telecommunications counsel. "You can't demand something that you don't know exists."
Enough users have, however, learned of this issue to support a small industry of Web sites and shops that can look up a phone's unlocking code for a fee. All you need for the service is your phone's 15-digit IMEI (international mobile equipment identity) number, a unique identifier stamped into each GSM phone.
David M. Rowell, publisher of a travel-related technology site called TheTravelInsider.Info, which offers the service for $5, said that most GSM phones require only tapping out the unlocking code in the proper sequence. But some models must be hooked up to special equipment to receive that number sequence.
Rowell said Nokia phones are easiest to unlock, while recent Motorola phones require extra hardware. In those cases, phone freedom has its limits: He won't unlock a phone if it requires mucking around with its circuitry, which he considers "too much hassle."
