Published September 10, 2012 / Associated Press

NEW YORK – T-Mobile USA, the only “Big 4” phone company that doesn’t sell the iPhone, now wants to snag used ones from AT&T.

Starting Wednesday, when Apple is expected to reveal a new iPhone model, T-Mobile will start advertising that AT&T iPhone owners who are out of contract can switch to T-Mobile.

“We expect that consumers will start trading in older devices,” said Harry Thomas, T-Mobile’s director of marketing. “For every person waiting in line for the next model, a lot of them have to find a secondary market for that older device.”

We expect that consumers will start trading in older devices.
– Harry Thomas, T-Mobile director of marketing

Apple hasn’t said anything about a new iPhone, but it is expected to announce the iPhone 5 at an event it has scheduled in San Francisco on Wednesday. Sales would likely start later this month.

Signing an iPhone up for T-Mobile service has been possible for years, and the company says it has more than a million iPhones on its network. But they suffer a big penalty in data speeds, taking about 50 times longer to download files than on AT&T’s network.

This year, T-Mobile is reshuffling the frequencies on its network, which will let it match or even exceed AT&T’s data speeds on iPhones. For now, that will be evident only in a few spots here and there in such cities as New York, Seattle, Las Vegas and Washington.

Sprint and Verizon iPhones of the “4” model won’t work on T-Mobile’s network at all. The later iPhone 4S will work if it’s been hacked, but that’s not something T-Mobile wants to get into.

AT&T iPhones have to be unlocked using codes that AT&T will supply after the customer’s contract is up.

T-Mobile, the U.S. cellphone business of Deutsche Telekom AG of Germany, has bought 3,000 iPhones and spread them out in its stores, so salespeople can demonstrate the iPhone working.

T-Mobile’s pitch will center on its unlimited data plan, which it reintroduced last week. AT&T stopped signing up new customers to unlimited plans two years ago, and now slows down service drastically for the rest of the billing cycle once those still on old unlimited plans reach a certain level of data usage.

In Atlanta and New York, T-Mobile will be giving away $100 gift cards to customers who sign their iPhones up for two-year contracts.