Comcast Corp., the largest cable television provider, won a lawsuit in which a Wisconsin company was seeking $2.2 billion, claiming infringement of a patent for using the Internet to make phone calls.

U.S. District Judge David Folsom in Marshall, Texas, ruled Thursday that Comcast didn't infringe a patent owned by closely held Caritas Technologies Inc.

Caritas claimed the Comcast Digital Voice service, with 1.3 million customers, infringed a patent issued in 2003. Caritas demanded $2.2 billion to settle the case, Comcast lawyer Daralyn Durie said in a statement.

"A ruling for Caritas could have had significant implications for all Voice over Internet Protocol providers," said Durie, of Keker & Van Nest in San Francisco.

Caritas, of Waunakee, Wis., and Comcast agreed the patent wasn't infringed under an interpretation last month by the judge. The ruling lets Caritas immediately take the case to the U.S. Court of Appeals for the Federal Circuit in Washington, which specializes in patent law.

Caritas claimed the patent covered all Voice over Internet Protocol, or VoIP, which sends voice transmissions via packets of data over the Internet or a private network. Folsom agreed with Comcast's argument that the invention uses voice transmitted through the more traditional circuits used for telephone calls.

Durie said that, had Caritas won, it could have sought royalties from both cable and phone companies that use VoIP to send voice over the Internet.