Microsoft filed complaints with the U.S. District Court in Seattle and the U.S. International Trade Commission. "We have a strong and robust patent portfolio that we will vigorously defend against infringement," said Kevin Kutz, Microsoft's director of public affairs, in a statement to the Reuters news agency.
"However, we remain open to resolving this situation through an intellectual property licensing agreement and we look forward to continued negotiations with Tivo," said Kutz.
Microsoft claims that the software that controls a number of Tivo DVR features, including the electronic program guide, program selection, remote controlled interface, and viewing restrictions, violate patents that lie behind technology in its Mediaroom DVR software.
Microsoft licenses Mediaroom to cable operators and other television service providers, including AT&T U-Verse, for use in their set-top boxes.
Microsoft is asking the federal court and the ITC to enjoin Tivo from selling its devices in the U.S. until the dispute is resolved. It's unlikely, however, that either body would impose such a hard sanction until there's a definitive ruling on the matter.
Microsoft and Tivo have previously locked horns in the courtroom. Microsoft also sued Tivo last year in California, alleging that Tivo had violated seven of its patents.
Beyond the individual patents in question, Tivo's use of Linux to power its set-top boxes may be another, underlying sore spot between the two companies. Microsoft has long held that Linux violates patents that relate to a number of Windows technologies, and has demanded that electronics makers that use Linux in their products pay a royalty fee.
Some vendors have complied, but Tivo's intransigence on the matter appears to be fueling what could be a long-running dispute between the two companies.