AT&T is sued for $1.35 billion over technology to synchronize smart devices

FILE PHOTO: The AT&T logo is pictures on a building in Los Angeles, California, U.S. August 10, 2017. REUTERS/Mike Blake

NEW YORK (Reuters) - AT&T Inc was sued on Tuesday for at least $1.35 billion by a Seattle company that accused the telecommunications giant of stealing its patented "twinning" technology, which lets smart devices such as watches and tablets respond to calls placed to a single phone number.

Network Apps LLC said AT&T abandoned joint development and licensing agreements for its technology in 2014 after realizing it would owe a "fortune" in royalties because the market for smart devices was exploding, only to then incorporate the technology a year later in its own product, NumberSync.