Associated Press: AT&T is once again experimenting with offering unlimited data plans to smartphone customers while promoting its DirecTV service, signaling a potential reversal of industry trends toward data caps and charges for big video watchers. AT&T is trying to capitalize on its $48.5 billion purchase of DirecTV last year. It’s announcing an unlimited data plan for cellphones, if you also get DirecTV or AT&T’s home-TV service, U-verse.