M/A Com Telecommunications Inc., a Germantown maker of very small satellite dishes used by businesses to transmit data and telephone conversations, was acquired yesterday by General Motors' Hughes Electronics Corp., a major maker of advanced electronic systems and components.

The acquisition makes GM Hughes Electronics Corp., with sales last year of $10.4 billion, the world's largest vendor of business satellite communications networks, GM Hughes Corp. President Donald J. Atwood said in a statement. The two companies signed a letter of intent in June, and GM formally approved the $105 million deal yesterday. M/A Com Telecommunications' 1986 revenue was $120 million.

M/A Com Telecommunications has been renamed Hughes Network Systems and will become a division of Hughes Aircraft Co., a subsidiary that makes more than half the nation's commercial satellites. M/A Com Telecommunications will add its line of 4- to 6-foot satellite dishes to the Hughes repertoire, enabling businesses to skip the telephone system entirely and cut costs.

GM Hughes officials said M/A Com Telecommunications, with about 1,000 employes, would not be integrated into Hughes Aircraft.

General Motors also owns Electronic Data Systems, the large computer systems integrator. M/A Com Telecommunications will also cooperate with EDS in marketing large data networks.

"Hughes already is the world's largest builder of communications satellites and one of the world's largest private satellite operators," Atwood said. "HNS {Hughes Network Systems} is the nation's leader in very small aperture terminal {VSAT} communications systems."

"The one-stop concept for satellite communications will provide corporations with a complete communication capability -- from satellites in 22,300-mile geostationary orbits to earth antenna installation, network management and on-site servicing," Atwood said.

Analysts said yesterday that the Hughes acquisition gives M/A Com Telecommunications a window to international sales, while giving Hughes a niche in the rapidly growing business of providing satellite data networks to commercial businesses that need to integrate communications among sales, inventory and other divisions. The sale concludes an effort by M/A Com, parent of M/A Com Telecommunications, to divest divisions not directly involved with the federal government.

Last year, M/A Com sold its M/A Com Information Systems, based in Rockville, to Centel Corp. of Chicago. M/A Com is a publicly held Massachusetts electronics maker.

The sale was "a good thing for M/A Com," said Bill Reed, an analyst with Link Resources, a New York market research firm specializing in electronic information. "It was ... a loosely organized company with no focus on their product line."

Hughes had been looking for ways to expand in data communications, Reed said. "It was a chance for them to expand into an equipment dish manufacturer to market to businesses interested in private line, high-speed private line data communications," he said.