The D.C. police department yesterday formally put into operation, a computer-assisted dispatching system that it hopes will send officers to the scene of an emergency within seconds instead of minutes.

The system, which has been in use since April and refined until its official inauguration yesterday, is largely the work of two police department civilian employes. Rick Davis, 34, and Harry Dandridge, 28, both systems analysts.

Because they and other department employes and officers developed the system, its cost was held to $1 million, compared to the $3.5 million that would have been charged by a private firm, police officials estimated.

"i'm pleased with the way it turned out," Davis said yesterday. "But it's kind of an emotional letdown. I've had a lot of fun working on it, but now that am I going to do?"

Police Chief Burtell Jefferson said the new system is the fruit of planning that began in 1974. It was decided then that the force needed a more sophisticated dispatching system -- one that would get helped to people well within the three to four minutes required them.

Under the old system, an emergency call was logged on a card by a clerk who located the address on a map, determined which police district the location was in, sent the card on a conveyor belt to the proper dispatcher who, finally, would summon a police car.

Now, a complaint receipt clerk types information about an emergency call into a computer terminal. Seconds later, the information appears on a screen in front of the proper dispatcher with data bout availability of police car, their location and verification of the complainant's address. Within seconds, help is on the way.

Davis and several others officials visited police departments in Dallas, Las Vegas, Jacksonville, Fla., and Newark, N.J., to observe their computer assisted dispatching systems.

The department also applied for, and received, a $600,000 grant from the Law Enforcement Assistance Administration to defray the costs of the system. An additional $400,000 of city taxpayers' money was provided.

The department put out bids for the computers and terminals and several companies offered to design and build the system. "With some fear and trepidation, we decided to build the system ourselves," said Davis, who holds a bachelor's degree in mathematics from Lehigh University.

The department brought two computers from Modular Computer Systems in Fort Lauderdale, Fla. and 45 terminals from ITT Courier in Phoenix, Ariz.

"we put in long hours," Davis said. "computers are somewhat compulsive. Once you get started you don't want to stop. It's not really work."

Davis and Dandridge said they spent many weekends, late nights and early mornings working on the system at police headquaters.

"it cost me three girlfriends," said Dandridge, who studied computer programming for four years at Washington Technical Institute.

Dandridge said if one computer fails to operate, the system has a back-up computer that will take over. If both computers fail, which Dandridge contends "is mathematically impossible," dipatchers can fall back on the old manual system.