The area's four existing cable television system have agreed to participate in an experiment designed to connect their subscribers to share data and video services, a consultant who put the deal together said yesterday.

The plan is the brainchild of Communication Technology Management Inc., a McLean consulting firm which designs and operates communications services, and NABU Manufacturing Corp. Ltd., a Canadian technology company.

"We're looking to use this project as a major learning center for us and the industry," said Thomas Crowley, executive vice president of CTM. "The Washington market is perched for substantial growth in cable. And Washington is unique because it is the government and association center."

The project involves a cable system owned by The Tribune Co. in Gathersburg, Warner Amex Cable's Reston system, the Alexandria Cable Co. and ARTEC in Arlington. Crowley said his company hopes to bring the recipients of coming franchise awards in Montgomery and Fairfax counties into the program.

The system, now in the design stage, is expected to be operating in about a year. Initially, only a handful of subscribers of the four systems will participate in the experiment. Ultimately, however, CTM hopes to use the technology to link cable systems across the metropolitan area.

Using a microprocessor in the home, the system will allow customers and businesses to use the cable to bring data and other services to their television sets. The system also offers the potential to permit teleconferencing, or televised meetings, and shopping and banking using the television.

"If the cable industry plans to keep growing, it has to stop operating as individual stand-alone systems," said CTM President Robert Schmidt, a Former president of the National Cable Television Association. "The world doesn't work that way. Advertisers don't buy a time in individual cable markets. They buy entire metropolitan areas."