AT&T Corp. and other phone service providers on Tuesday moved closer to ending a long-running infringement suit over systems for transmitting high-frequency data signals over telephone networks.
The ruling, which granted the defendants’ motion for summary judgment of noninfringement, came more than six years after United Access Technologies Inc. had first accused AT&T, Frontier Communications Corp. and Qwest Corp. of infringing patents for a signal interface known as a Digital Subscriber Line Access Multiplier, or DSLAM.
