The Justice Department sharpened its objections Wednesday to a threatened shutdown of the BlackBerry e-mail system, saying it would be difficult to close it without affecting government users.
Separately, the U.S. Patent and Trademark Office took another step Wednesday toward invalidating a patent that is at the center of the bitter legal feud. The patent covers a wireless email system, which is at the heart of the long-running legal dispute, reports CBS News MoneyWatch correspondent Alexis Christoforous.
Stephen Maebius, a Washington patent attorney not involved in the case, said the action was not final but does bring the patent office closer to expected final rejections of the patents held by NTP.
NTP Inc., an Arlington, Va.-based company, has convinced a federal jury that its patents have been infringed by Research In Motion Ltd., the Canadian operator of the BlackBerry network, and is seeking a court ruling to turn off the network.
The judge in the case has indicated he could decide on NTP's request following a scheduled Feb. 24 hearing.
NTP has said such an injunction would not apply to government BlackBerry users, who may account for up to 200,000 of the company's 4.3 million customers.
In a court filing Wednesday, NTP said there were "readily administrable" ways to exclude government and emergency users from a shutdown.
The Justice Department has previously questioned that assertion, and in Wednesday's court filing said it could not find that NTP's plans "can be realistically implemented."
The government provided a list of 138 agencies that may need to be excluded from a shutdown, along with their related contractors. The list includes the Central Intelligence Agency, the Army and the National Security Agency.
The government left the door open for an injunction that would leave the network in operation but stop sales of new BlackBerries to private users.
For its part, RIM has agreed with the Justice Department that it would be difficult to separate government from private BlackBerry users. In a filing Wednesday, it also argued that public interest in the network extends beyond government users. For example, it said, the financial services industry relies heavily on the devices.
In its filing, NTP replied that identifying government users is RIM's responsibility, and any difficulties doing so shouldn't prevent an injunction.
The patent office has already preliminarily rejected all five patents at the heart of the NTP's lawsuit against RIM.
However, the trial judge hearing the case has indicated himself unwilling to await final word from the patent office.
Despite the threat of a BlackBerry blackout, many analysts think an actual shutdown is unlikely because putting RIM out of business would make it harder for NTP to collect a big settlement.