NEW YORK — Unlimited wireless data is back. After sliding off the menu of cellphone plans, data plans with no caps are making a comeback at smaller wireless companies trying to compete with AT&T and Verizon.

NEW YORK — Unlimited wireless data is back. After sliding off the menu of cellphone plans, data plans with no caps are making a comeback at smaller wireless companies trying to compete with AT&T and Verizon.

T-Mobile USA, the nation's fourth-largest cellphone company, said Wednesday that it will start selling an unlimited-data plan again on Sept. 5. A day earlier, No. 5 carrier MetroPCS cut the price of its unlimited-data plan.

The moves by T-Mobile USA and MetroPCS, neither of which sells the iPhone, come as their three larger rivals are thought to be gearing up to begin selling the iPhone 5 in a month or so. No. 3 carrier Sprint Nextel Corp. already has an unlimited-data plan.

AT&T, the nation's second-largest carrier, stopped signing up customers for unlimited data plans two years ago, while No. 1 Verizon Wireless stopped last year.