Visto, which provides push e-mail services to mobile telecomms firms, has filed a complaint alleging that RIM has infringed four of its patents. The firm is seeking an injunction and monetary damages from the Canadian firm.

Visto says the complaint was filed immediately after a court in Texas' Eastern District awarded it damages of about $3.6 million in a patent infringement lawsuit filed against e-mail software firm Seven Networks. The jury found that Seven's mobile e-mail service infringed on a system that Visto had created over the past decade.

Brian Bogosian, Visto's chairman, president and CEO, says: "There was no ambiguity in the jury's decision. Likewise we believe that RIM's infringement of Visto's technology will be halted. Our case against RIM is based on similar technology, law and patents as the case we have just won in federal court against Seven Networks."

Bogosian adds: "Under the law, which protects consumers from products that contain infringing technology, RIM should not be able to sell the Blackberry system."

But in a statement, RIM says: "Visto's patent claims as directed against Seven Networks refer to a different type of system than RIM's technology. RIM believes it does not infringe Visto's patents and will file its legal response in due course."

The vendor says it is fully prepared and equipped to deal with the matter and it does not expect its customers to be impacted by Visto's complaint. In addition to challenging validity and infringement, RIM says it will now also consider asserting its own patents against Visto.

RIM says it is unlikely that any material court proceedings in this litigation could begin prior to the middle of 2007.

News of Visto's lawsuit comes barely two moths after RIM agreed to pay $612.5m to settle a four year patent infringement dispute with US-based NTP.