Since this story was originally reported, it has been updated to correct the description of the relief sought by Visto.BlackBerry users have another patent lawsuit to worry about. Just weeks after their service was nearly shut down by a lawsuit brought by NTP, the wireless e-mail devices are now being threatened by legal action brought by software provider Visto.In a lawsuit filed Friday in the U.S. District Court for the Eastern District of Texas, Visto claims that Research In Motion Ltd.\u2019s (RIM\u2019s) BlackBerry service violates four Visto patents. The lawsuit seeks unspecified damages and asks the court to shut down BlackBerry\u2019s service in the U.S. The patents in question relate to the accessing and synchronizing of information over a network and are fundamental to the BlackBerry service, said Brian Bogosian, Visto\u2019s chairman, president and chief executive officer, speaking during a Monday conference call. "RIM should not be able to sell the BlackBerry system," he said.Visto\u2019s lawsuit was filed on the same day a Texas jury awarded the company US$3.6 million in a similar patent lawsuit against competitor Seven Networks. Three of the four patents in the RIM lawsuit were also invoked in the Seven Networks lawsuit, Visto said.RIM downplayed the significance of the Seven Networks decision. "Visto\u2019s patent claims as directed against Seven Networks refer to a different type of system than RIM\u2019s technology," the BlackBerry vendor said in a statement. "RIM believes it does not infringe Visto\u2019s patents."RIM is considering a patent countersuit against Visto, the company said. Founded in 1996, Visto\u2019s e-mail and calendaring applications are used by more than 200,000 customers worldwide, and are available through a number of wireless services including those of AT&T, Bell Canada and Vodafone Group.Though Visto alleges that RIM has been violating its patents for years, the company had a couple of reasons for waiting until now to file the lawsuit, Bogosian said. Visto, which is also suing Microsoft and Good Technology for violating some of these same patents, did not want to "dilute" its legal resources by launching the suit before the Seven Network judgment, he said.RIM settled its long-running legal battle with NTP in March, paying NTP $612.5 million to settle all of its claims.This settlement was also a factor in Visto\u2019s decision to move forward with its own lawsuit, Bogosian said. "There was a very significant and real risk that RIM would be shut down," he said. "In our opinion, it did not make sense to launch a litigation at that time."Visto is now ready for a "protracted battle" against the BlackBerry maker, Bogosian said. The company, based in Redwood Shores, Calif., has no plans to launch similar lawsuits outside of the United States, he added.Either way, a resolution in this matter could be years away. It may take until the middle of 2007 for "material court proceedings" to begin, RIM said.Bogosian also left the door open to the possibility of a settlement that would not involve a BlackBerry shutdown, provided "a reasonable resolution" could be found. "We\u2019re also business people," he said."RIM does not expect its customers to be impacted by Visto\u2019s complaint," the company said.-Robert McMillan, IDG News ServiceFor CIO\u2019s past coverage of the RIM\/NTP infringement suit, read BlackBerry on the Edge.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.