The agreement allows Apple and Cisco to use the iPhone brand on their own products. Also, the companies said that they would explore opportunities for interoperability in the areas of security and of consumer and business communications.

The brief announcement made no reference to any financial agreement, nor did it specify how the two companies might work together. Representatives for Apple and Cisco declined to comment further, citing confidentiality restrictions.

Cisco sued Apple for trademark infringement in January after Apple unveiled its long-awaited multimedia phone called the iPhone, a name claimed by the network equipment maker. Cisco also charged in its complaint that Apple had attempted to get rights to the iPhone name several times, but after Cisco refused, created a front company to try to acquire the rights another way, according to the lawsuit.

Cisco obtained the iPhone trademark in 2000 when it acquired Infogear, a small Redwood City, Calif., start-up that developed consumer devices that allowed people to access the Internet without a PC. Infogear had actually registered the iPhone trademark in March 1996.

Cisco's home networking division, Linksys, has been using the iPhone trademark on a new family of voice over IP phones since early last year, Cisco said. In December, Linksys expanded the iPhone family with additional products.

The two companies had been in extended negotiations to settle the lawsuit, and a second extension of the talks was set to expire Wednesday.

The iPhone, which Steve Jobs unveiled in January at the Macworld Expo, will allow users to listen to music, make phone calls, send text messages and e-mail, surf the Web, and take and upload photos. It's expected to be available in the United States on Cingular's network starting in June and will come in two versions, a 4GB model for $499 and an 8GB model for $599.