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. According to a complaint filed in Manhattan federal court, NumberSync uses the “same concept and architecture” with only “cosmetic changes,” and its purported “inventors” were the same AT&T personnel who had worked with the plaintiffs. Network Apps, which was once known as Mya Number, said Dallas-based AT&T has not paid required royalties since October 2015. It is seeking at least $450 million of damages, which it wants tripled to reflect AT&T’s alleged “willful and egregious infringement,” plus royalties for any future infringements. AT&T said it will review the lawsuit and respond in court. Network Apps’ founders, John Wantz and Kyle Schei, in a joint statement said “AT&T’s decision to steal our technology” has forced them to scale back operations significantly. “Our technology is an eloquent solution for a critical problem at a critical time in the industry,” they added. According to AT&T’s website, NumberSync lets consumers make and receive calls on smartwatches, tablets, computers andcompatible Alexa-enabled devices without having to download appsor engage in “call-forwarding acrobatics.” The case is Network Apps LLC et al v AT&T Inc et al, U.S.District Court, Southern District of New York, No. 21-00718.