However, Apple said the lawsuit was "silly" and that Cisco's trademark registration was "tenuous at best".
Apple spokesman Alan Hely explained: "There are already several companies using the name iPhone for Voice Over Internet Protocol (VOIP) products."
"We are the first company to ever use the iPhone name for a cell phone, and if Cisco wants to challenge us on it we are very confident we will prevail."
But Cisco Systems, which has owned the iPhone trademark since 2000, said it thought Apple would agree to a final document and public statement concerning the disputed trademark.
Cisco, which supplies networks, also maintained that it would seek to prevent Apple from "infringing upon and deliberately copying and using" the trademark.
