BlackBerry maker countersues Visto

Research In Motion is fighting back against the latest allegations that its BlackBerry mobile email device infringes on patents.

The BlackBerry maker on Monday filed a countersuit to a suit filed last week by mobile email vendor Visto. Visto accused RIM of infringing on four patents describing components of a mobile email system that allow users to synchronise messages and data with that from remote locations, including those protected by firewalls.

RIM, in turn, has asked a federal judge to declare three of the disputed patents held by Visto invalid. RIM also reasserted that it has not infringed on the patents in question.

At the time its suit was filed in federal court in the Eastern District of Texas, Visto was fresh off a patent infringement victory involving similar claims in the same court over another rival, called Seven Networks. Three of the four patents described in the RIM suit also formed the basis for the Seven dispute. Other related suits are pending against several other companies, including Microsoft and Good Technology.

In a telephone interview on Friday, Daniel Mendez, Visto co-founder and senior vice president, indicated he was not discouraged by RIM's action. "We believe very strongly that they do infringe," he said.

RIM representatives did not respond immediately to requests for comment.

In March, RIM averted a court-imposed shutdown of its BlackBerry service by reaching a $612.5m (£330m) settlement with patent holder NTP, which had already prevailed in earlier stages of the infringement litigation. Some of those disputed patents have already been rejected by the US Patent and Trademark Office, though such decisions can still be appealed.

According to the court docket, Visto has 20 days to respond to RIM's claims. RIM chose to file its own suit in a different Texas federal court located in Dallas. Visto had filed all of its previous patent infringement suits in Texas's Eastern District in Marshall, Texas, which has earned a reputation for offering speedy outcomes and favourable treatment to patent holders.

"It is one of the few courts in the US that has, number one, an extensive experience with patents and, number two, at the time (of the first filings), it was the fastest venue to get our case heard by a jury," Mendez said.

Analysts at Gartner Research predicted this week that Visto and RIM could take years to resolve the spat. They concluded, however, that users and vendors of each company's products would not be affected anytime soon.