Up to 44,000 business and residential phone lines in the District did not work or worked intermittently yesterday afternoon because of computer problems at Chesapeake & Potomac Telephone Co.

C&P spokesman Mike Houghton said the telephone company had equipment trouble in its central office at 2055 L St. NW between 2:20 and 4 p.m. The problem was fixed when telephone company personnel shut off connections to the 44,000 lines for a split second, and then turned the connections back on.

C&P has more than 780,000 phone lines in the District.

During the period of nearly two hours, telephone customers often were unable to make or receive calls, Houghton said. The telephone company had not diagnosed the precise cause of the problem late yesterday.

Houghton said telephone exchanges that could have been affected included 334, 429, 457, 676, 775, 828, 857, 862, 223 and 659.

Neither the White House nor the General Services Administration, which handles phone service for most federal agencies, reported problems with phone service yesterday afternoon.

George Washington University Hospital experienced a delay in getting dial tones, but only for about 10 minutes, said spokeswoman Irene Haske.

John Riddell, assistant chief of communication for the Associated Press, said the news agency could receive calls but not make them between 2 and 4 p.m. "You don't know what's going on in terms of news. . . . I thought someone cut the cables. I was worried," Riddell said.

The Washington Post Co. also experienced problems yesterday afternoon with getting dial tones and with incoming and outgoing calls.

One State Department official said, "I have heard corridor gossip [that people] weren't getting calls in or out."

The D.C. police department reported no problems receiving 911 emergency calls and said there was no appreciable drop-off in calls to the number. C&P's Houghton said some people may have experienced problems reaching 911 if they were calling from an affected exchange number. "It could be that no one had problems with 911," he said.

The problem is not considered usual, said Houghton. "They don't know what caused the problem, but it's up and working fine . . . . For all intents and purposes, they reset the system, turned off all the connections and then turned them back on again -- like resetting a computer."

"They are researching and analyzing the tapes to see what caused the problem," Houghton said. He said such problems can occur when heavy calling is taking place in the District, but that such was not the case yesterday.

"We ruled it out . . . . A lot of people aren't working downtown [this week], and calling volumes are down dramatically." The telephone system "sometimes can get confused," and think there is heavy calling when there isn't, Houghton said.