Weeks after paying $80 million to settle patent charges brought by Sprint Nextel, Vonage Holdings—the nation’s largest independent provider of voice-over-Internet protocol (VoIP) services—reached an agreement with Verizon Communications that will put an end to further litigation between the companies. A Virginia district court judge barred Vonage last spring from signing new voice-over-Internet protocol (VoIP) customers after a jury found Vonage guilty of infringing three VoIP-related patents held by Verizon. Although the Federal Circuit later issued a stay of the district court injunction, a three-judge panel of the Federal Circuit upheld the jury’s decision last month on two of the three patents in question. Under the settlement agreement announced yesterday, Vonage would pay Verizon $80 million or $117.5 million, with the exact amount to depend upon a Federal Circuit en banc decision that Vonage has requested with respect to the two Verizon patents upheld last month. If the full court panel rules in favor of Vonage, Verizon will receive the smaller amount. Either lump sum payment would also cover the third Verizon patent that was remanded to the lower court. Although Vonage praised the settlement as one that “removes the uncertainty of legal reviews,” the company’s legal woes continued this week, as AT&T became the latest major carrier to accuse Vonage of patent infringement. AT&T’s lawsuit, filed with the U.S. District Court in Madison, Wisconsin, was disclosed in documents submitted by Vonage last Friday to the Securities and Exchange Commission. The complaint concerns a patent awarded to AT&T in 2002 that enables callers to use standard telephone equipment to make VoIP calls. Charging Vonage with willful infringement, AT&T told the court that it had failed in recent attempts to reach a licensing agreement with Vonage. Sources also confirm that AT&T is seeking injunctive relief as well as unspecified monetary damages. Asserting, however, that, “we’re moving forward and putting litigation behind us,” a Vonage spokesman noted: “it would be our preference to have an amicable solution with AT&T.”