Cisco is suing Apple for using the iPhone name in the US, where the company owns the iPhone trademark.

The lawsuit was filed in a US District Court in northern California, and seeks to prevent Apple from “infringing upon and deliberately copying and using Cisco's registered iPhone trademark”, according to a statement from Cisco.

Linksys, a division of Cisco, released a product called the iPhone just before Christmas. Linksys's iPhone is the name given to a series of VoIP phones for business and home users.

“Cisco entered into negotiations with Apple in good faith after Apple repeatedly asked permission to use Cisco's iPhone name”, said Mark Chandler, senior VP and general cousel at Cisco, in a statement.

“There is no doubt that Apple's new phone is very exciting, but they should not be using our trademark without our permission."

“Today's iPhone is not tomorrow's iPhone. The potential for convergence of the home phone, cell phone, work phone, and PC is limitless, which is why it is so important for us to protect our brand," Chandler concluded.

"We think Cisco's trademark lawsuit is silly. There are already several companies using the name iPhone for VOIP products, and we believe that Cisco's US trademark registration is tenuous at best," said Apple spokesperson Alan Hely.

"We are the first company ever to use the iPhone name for a cell phone, and if Cisco wants to challenge us on it we are very confident we will prevail."

Cisco has apparently owned the trademark since 2000.