Research in Motion's (Rim's) recent $450m legal settlement ending the long-running patent infringement battle with NTP does not rule out the possibility of further NTP legal action against other wireless email vendors including IBM and Microsoft, Gartner has warned.

Under the terms of the agreement which was reached on 16 March, Rim will pay NTP $450m in cash (of which $137m is already held in escrow).

The deal covers past and future Rim products, services and technologies, as well as any partnerships Rim may enter into with network carriers, distributors, hardware vendors, suppliers or software developers.

Although Rim's decision to settle with NTP, a patent holding company, removes a major stumbling block for enterprise wireless email, it is unlikely to draw a line under NTP's legal campaign to protect its intellectual property, according to Gartner analysts Ken Dulaney, Todd Kort and Monica Basso.

"This settlement, and a similar deal between NTP and Rim competitor Good Technology, eliminates a major obstacle to wireless email deals in the US," said the analysts.

"However, Gartner believes that NTP may make similar claims against other vendors, including such major players as IBM and Microsoft, both of which have stated that they do not believe their technologies infringe on NTP patents."

Gartner also believes that Rim was wise to settle the NTP patent infringement suit, even though the payment is among the largest patent settlements in US history.

"By settling now, Rim avoids the unpleasant possibility of having to pay royalties to NTP on an ongoing basis, and also removes the uncertainty that has troubled its software licensing efforts," the analysis noted.

"Due to NTP-related concerns, Rim's software licensing programmes, BlackBerry Connect and BlackBerry Built-In, have generated only modest interest from hardware vendors since their introduction in 2003.

"These vendors have been understandably concerned about becoming entangled in disputes with NTP, and have sought indemnification from Rim before selling products based on its technology in the US market."

Gartner advises hardware vendors, telecoms providers and others considering wireless email deals to consider the possibility of patent litigation in all strategic planning.

Enterprises considering adopting BlackBerry technology should continue with existing plans, because this agreement is not likely to change pricing or other factors, according to Gartner.