The unit, Motorola Mobility, said the infringements relate to a wide range of functions in Microsoft’s PC and server software, Windows mobile software and its Xbox game console.
The move comes just a day after Microsoft accused the phone maker of charging excessive royalties on network technology used in the software company’s Xbox.
Last month, Microsoft accused former ally Motorola of infringing nine of its patents in Android-based smartphones, which run on software built by Google Inc GOOG.O.
“It is unfortunate that Microsoft has chosen the litigation path rather than entering into comprehensive licensing negotiations,” Kirk Daily, Motorola’s corporate vice president of intellectual property, said in a statement on Wednesday.
Microsoft did not immediately have a comment on the suits.
Motorola Mobility’s complaints, filed in federal courts in Florida and Wisconsin, are the latest in a complicated series of legal actions between various phone makers and software firms over who owns patents to the new technology.
Finnish phone maker Nokia NOK1V.HE sued iPhone maker Apple Inc AAPL.O last year, and Apple subsequently sued handset maker HTC Corp 2498.TW. Software maker Oracle Corp ORCL.O has also sued Google over Android software.
Reporting by Elinor Comlay and Bill Rigby; Editing by Gary Hill and Lincoln Feast
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