OTTAWA, March 3 Â The prospect of a shutdown of BlackBerry wireless e-mail service in the United States evaporated today as the two companies in the patent dispute reached a $612.5 million settlement.

While more costly than an attempt last March to settle the case for $450 million, today's deal gives Research in Motion, the BlackBerry's Canadian maker, an unconditional right to use patents held by NTP Inc., a closely held intellectual property holding company in McLean, Va.

BlackBerry customers had faced the prospect of installing new software that Research in Motion promised would avoid NTP's patent claims. But that process was likely to be costly, and it faced legal uncertainties.

"There's been a collective sigh of relief," said Ellen Dailey, an analyst with Forrester Research. "R.I.M. knew that by not settling, they were going to put tremendous pressure on their customers."