Online Computer Systems Inc., a Germantown, Md.-based computer research and services company, has agreed to be acquired by Reed International, P.L.C., of London, for an undisclosed amount.

The terms of the merger assure Online continued autonomy in operations, while providing the "deep pockets" necessary for financing international marketing and developing new ways of delivering information through computer and video technology, Online's founder and president, William H. Ford Jr., said yesterday.

Reed is a holding company with about $2.5 billion in annual sales, and subsidiaries such as Reed Publishing, Cahners Publishing Co. and Reed Worldwide Exhibitions. Reed is one of several international media companies seeking to diversify by acquiring communications properties in the large and lucrative U.S. market. Reed had stated publicly that it wanted to move into the fast-growth computer software and electronic media areas.

"Reed will provide Online with the strength to grow as fast as the market permits, and on our part, Online provides Reed with the expertise and technical proficiency to enter a highly specialized, high-growth, emerging industry," said Ford, who will continue to serve as president.

"The strategy now is to build the company into one of the premier electronic publishing companies of the next decade," he said.

Online, a privately held company founded in 1979, had revenue of more than $6 million last year and had assets worth about $1 million at the time of the merger agreement, Ford said. The company does not disclose net revenue figures, but says it has been profitable since it was founded.

The company will continue to be based in Germantown, Ford said. Online has about 85 employes between its local office and its Raleigh, N.C., research and manufacturing facility.

Online serves government and business clients by designing and producing computer systems to allow easy access to large quantities of information, both printed and visual. The company, for example, has helped the Pentagon's Army Library automate its operations.