Microsoft today sued Motorola, alleging several of the cell phone maker's Android devices infringe on Redmond's patents.
Microsoft both sued Motorola in U.S. District Court in Washington and brought a complaint before the International Trade Commission. Microsoft alleges Motorola infringes on nine Microsoft patents related to key smartphone experiences such as syncing e-mail, calendar, and contacts, and notifying applications about changes in signal strength and battery power, Microsoft said. The complaint cites Motorola's Droid 2 phone as an example.
"We have a responsibility to our customers, partners, and shareholders to safeguard the billions of dollars we invest each year in bringing innovative software products and services to market," Microsoft deputy general counsel Horacio Gutierrez said in a statement.
The suit comes as Microsoft is trying to line up phone makers to use its Windows Phone 7 operating system. Although Google-developed Android can be used free of charge, Microsoft has been trying to make the case that phone makers should consider the potential intellectual-property issues and related costs before going with Android.
Earlier this year, Apple sued HTC--which makes both Windows Phone and Android phones--over patent issues. Apple expanded its suit in June, adding two additional patents. Then HTC responded with a countersuit, alleging Apple infringes five of its patents. Microsoft provides those using Windows Mobile and Windows Phone operating systems with patent protections, something that Google has yet to commit to.
Motorola was once a significant licensee of Windows Mobile, but in recent years has shifted largely to Android.
Motorola had no immediate comment on Microsoft's suit. A Google representative did not immediately respond to a request for comment.
In a blog posting, Gutierrez defended Microsoft's need to take legal action.
"The rules of the road are long-established in the software industry, and fundamental to the industry's growth and economic impact is respect for others' intellectual property rights," he said. "Our action today merely seeks to ensure respect for our intellectual property rights infringed by Android devices; and judging by the recent actions by Apple and Oracle, we are not alone in this respect."
A copy of Microsoft's District Court suit is embedded below:
Micrsoft Motorola Patent Suit More details to come.
CNET's Tom Krazit contributed to this report.