Three years after being sued by Cisco Systems for giving its iPhone the same name as a Cisco product, Apple has taken another page from the Cisco playbook, renaming its iPhone operating system, iOS.

Apple CEO Steve Jobs unveiled the new iOS name at his company's Worldwide Developers Conference in San Francisco Monday. He said that it didn't make sense to call the operating system the iPhone OS, given that it is also being used to power things that aren't iPhones, namely the iPad and iPod Touch.

IOS just happens to be the same trademarked acronym that Cisco uses for its Internetwork Operating System, and that could have spelled trouble for Apple. Cisco sued Apple in January 2007, after Apple announced the iPhone, claiming that it had previously registered iPhone as a trademark for its IP-enabled telephones.

However, this time around there won't be any lawsuit brought by the networking giant. That's because Apple and Cisco came to terms ahead of Monday's announcement.

"Cisco has agreed to license the iOS trademark to Apple for use as the name of Apple's operating system for iPhone, iPod touch and iPad," said Cisco spokeswoman Kristin Carvell. "The license is for use of the trademark only and not for any technology."

Carvell declined to provide the terms of the licensing agreement or to provide more information on the deal. Apple did not respond to a request for comment.

Apple is taking a conservative approach by licensing the name from Cisco, whose routers and switches are quite different from Apple's products, said Michael Atkins, an intellectual property partner with the Graham & Dunn law firm in Seattle. "I don't know that an operating system for the iPad and the new iPhone would fall within the description of goods that Cisco had explained in its [trademark] registrations," he said. "I think it's more of an effort to avoid a fight down the road."

Cisco IOS wasn't the only trademark Apple licensed Monday. It is also bought the name FaceTime -- used for Apple's new video chat application -- from a social networking security software company. FaceTime, the security company, will change its name over the next few months, completely transferring the name to Apple.

(Steve Lawson in San Francisco contributed to this report.)

Robert McMillan can be reached at robert_mcmillan@idg.com. He is on Twitter at: http://twitter.com/bobmcmillan.