Cox Communications this week asked the Supreme Court to hear its challenge to a decision that its VoIP service infringes various Sprint patents.
Sprint claimed Cox was employing the patents in its voice service without permission.
In a filing for a writ of certiorari, Cox told the Supreme Court that the U.S. Court of Appeals for the Federal Circuit errored when it overturned a lower court decision that Cox had not violated the Sprint patents. That is the federal appeals court that specializes in patent and trademark cases.
Cox had claimed that Sprint's patents were "indefinite" and impermissibly asserting a claim over "every way of performing a function on a general-purpose computer."
Cox asserts that "It has long been 'well understood' that a patentee may not by claiming a patent on the result or function of a machine extend his patent to devices or mechanisms not described in the patent."
The company says the Federal Circuit broke with Supreme Court precedent, the Federal Circuit's own precedents, and turns the "indefiniteness" standard on its head.
It says the Supreme Court needs to take the case "to confirm that functionally claimed structures are indefinite—a question of immense practical importance, especially for computer- and software-implemented inventions."
Cox also points to a circuit split over whether "general purpose computers" provide "sufficient structure for software functions." The Federal Circuit found that "processing system" was a sufficiently "definite" structure.
Differing decisions from lower courts is one of the reasons the Supreme Court will agree to hear an appeal.