Blackberry plan to avoid shutdown

Blackberry devices are used by 3 million people in the US

Blackberry-maker Research In Motion (RIM) has developed a "software workaround" to maintain its service in the face of a possible US shutdown.

The Canadian-based firm said the software patch would enable its handheld e-mail devices to work even if a US court ruling goes against it.

RIM is embroiled in a patent row with US firm NTP, which is demanding the popular service be turned off.

A ruling on NTP's bid for an injunction against RIM is due later this month.

NTP, a software firm, says the Blackberry device breaches its patents.

A move to switch off the service would potentially hit more than three million users in the US.

Legal tussle

RIM said it was negotiating with NTP, but described the US firm's offer to license the disputed technology as "untenable".

"RIM has developed these software workaround designs as a contingency to allow the Blackberry service to continue should the court implement an injunction in the current litigation involving the NTP patents," RIM said in a statement.

It said the software patch altered the way e-mail messages were delivered and sorted, but added that users would not "see any changes in the way they use the Blackberry device".

The tussle between the two companies dates back to 2002, when patent-holding company NTP successfully sued RIM in a lower court and won an injunction in 2003 to halt US sales of the Blackberry and shut down its service.

However, that ruling was delayed pending appeal.

Earlier this month the US government asked a federal judge to hold off from a possible shutdown of the Blackberry service because of the system's popularity among key government employees.