Lawyers for NTP, which ison charges of patent infringement, reiterated their request that the judge impose an injunction unless the two sides reach a settlement.
"NTP's proposed form of injunction provides a reasonable (30-day) grace period for RIM's customers and partners to switch to alternative products before the injunction affects them," NTP said in its court brief.
The injunction proposed by NTP would alsoof the BlackBerry, as well as emergency first-responders from any service cutoff.
RIM said in its filing that it would be "difficult, if not impossible" to cut off service to some users while maintaining it for the government.
Citing the "exceptional public interest" in maintaining uninterrupted BlackBerry service, especially to workers in national security and health and safety, RIM called on U.S. District Judge James Spencer to back away from issuing any injunction and to convene a new trial.
"The public interest here far outweighs NTP's economic interests, which are fully compensable through damages," RIM said in its brief.
RIM also saidto avoid infringing NTP's patents would cause "concern" among users and service providers because it would require reloading software on servers and the handheld devices.
But NTP downplayed the hardship that RIM's commercial customers would suffer from a shutdown, saying "there are "a number of licensed alternatives which can fully meet their requirements."
Among the alternatives to the BlackBerry is the Treo 650 smart phone made by computer and smartphone maker. Both devices offer phone and e-mail service, access to personal calendars and the Internet.
Spencer has ordered both sides to file response briefs on Feb. 1, and the judge is expected to schedule a date soon for a hearing on the arguments.
NTP filed a patent infringement lawsuit against RIM in 2001, and a jury in Richmond, Va., found in NTP's favor in 2002. In 2003, Spencer granted an injunction that would have halted U.S. sales of the BlackBerry and shut down its service, but stayed the injunction pending appeal.
An appeals court in August scaled back the ruling against RIM, but upheld some patent infringement claims.
Requests by RIM to get the courts to stay the case, including a, have failed.
On Nov. 30,and refused to force NTP to accept $450 million from RIM as a settlement.
Still before Spencer is the question of what effect, if any, the appeals court ruling should have on the injunction and damages being sought by NTP.
In a separate proceeding, RIM is challenging the validity of the NTP patents before the U.S. Patent and Trademark Office.
The two sides have held talks to settle the court case in recent months. In the brief filed on Tuesday, NTP argued that it had made a reasonable offer to settle the case, but had been rejected by RIM.