Cisco sued Apple on January 10, claiming that in launching the iPhone at the Macworld conference, Apple is infringing on Cisco's trademark.

Although Apple's predicted move into cell phones has unofficially been called iPhone for years -- given that many of Apple's products begin with a lowercase "i," including iMac, iPod, and iLife -- Cisco obtained the trademark in 2000 after the acquisition of InfoGear, which had been granted the original trademark in 1996.

In its response to Cisco's lawsuit, Apple is now claiming that it is the first company to use the term iPhone to apply to a cell phone.

Trademark Spat

The wrangle over the trademark is likely to be a contentious battle, with "strong arguments on both sides," noted David Radack, chair of the intellectual property department of Pittsburgh-based law firm Eckert Seamans.

"Cisco has a good position, since it can demonstrate long-term use, along with the claim that it has plans to expand that use," said Radack.

Apple, on the other hand, can point to its line of "i" products to demonstrate what is called a family of trademarks, Radack explained. That argument might be less effective, however, given that other companies also put "i" in front of various products, such as Griffin Technology with its iTrip and iVault products.

Generic Issues

Perhaps the most difficult legal tactic in the mix is Apple's claim that "iPhone" is a generic term, Radack said, and therefore cannot be used as a trademark.

"Apple could find this argument to be a double-edged sword," said Radack. "It would allow them to use the term 'iPhone,' but it would let everyone else use it, too. Motorola could come out with an iPhone and there's nothing they could do to stop it."

What the lawsuit will probably revolve around is what is called a "likelihood of confusion," he added. The court would look at whether someone who sees the term "iPhone" would confuse Cisco's offering with Apple's.

Also at play could be "reverse confusion," which means that if Cisco expanded its iPhone line, consumers could think the company was copying Apple, even though Cisco owns the trademark.

"Basically, these are two 800-pound gorillas going to battle," said Radack. "It should definitely be an interesting case."