Why did iPhone talks collapse?

…could jeopardise or limit future plans to integrate with other companies' technology or with technology that Apple may develop itself, he speculated.

Historically Apple has been very selective about the companies it works closely with.

"Apple likes to keep control of the environment in which their products operate, so that nothing takes away from the value of the products," he said. "And I can see Apple not wanting to tie themselves to any one technology, even though I really don't think they plan to make the iPhone a VoIP phone."

By contrast, it's easy to see why Cisco would want to work closely with Apple. For one, Cisco may want to ensure that the Apple iPhone works well with its Linksys wireless routers when users are downloading music or content via their Linksys Wi-Fi home network. Even though Wi-Fi is a standardised technology and products from different vendors work well together already, there could be small advantages gained through special interoperability, said Lisa Pierce, an vice president with Forrester Research.

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"Interoperability is a funny thing," she said. "In a way it's like a parking deck, and there are different levels of how well products using the same standard technology work together. If products are interoperable, they've been tested and modifications have been made to ensure they work optimally."

But some analysts wonder if Cisco may have been looking for a deeper level of integration. In the iPhone family, Linksys has integrated software from Skype and Yahoo. There is a chance that Cisco was hoping to strike a similar deal with Apple that may have eventually put some of Apple's music software on the Cisco/Linksys iPhones.

Cisco may also have been trying to take a first step toward an even more comprehensive partnership with Apple, said Zeus Kerravala, a vice president at the Yankee Group.

"I've always thought an Apple/Cisco partnership would make sense," he said. "If they leveraged each other's strengths — Apple's understanding of consumers and user workflow and Cisco's expertise in networking and infrastructure — they'd make a powerful team."

But while Cisco has a track record of successfully partnering with other large companies, such as IBM or HP, Apple does not typically operate this way.

And as a result, Keravala conceded that an Apple/Cisco partnership is unlikely to happen. "It's just not in Apple's DNA."