A Montgomery County electronics company has purchased land for a major new office and manufacturing complex along the I-270 corridor in Germantown.

Digital Communications Corp., which makes electronics equipment for satellites and other communications systems, has bought 51 acres of land immediately south of the Germantown exit on the east side of I-270 at a cost of $1 million, according to Digital Vice President Jack Shaw.

The firm will be located opposite the offices of the Energy Research and Development Administration and adjacent to the new Germantown campus of Montgomery College.

The company expects to begin construction in late October or early November on two buildings containing about 150,000 square feet. They are scheduled to be completed by the end of 1979 at a cost of $5 to $7 million. The company plans to consolidate its two offices in Gaithersburg and one office in Rockville in the new structures.

The firm, which employs 300 to 400 persons, estimates that its payroll will rise to 500 as it prepares to move to its new quarters.

The company forsees the possibility of completing, in the next three to four years, a complex with a total of six buildings which would be connected with an atrium in the middle, according to Shaw. The entire complex could cover some 400,000 to 600,000 square feet, Shaw said. By comparison, the GEICO complex in the Friendship Heights area occupies about 500,000 square feet, according to county officials.

The company won support for its project from the Montgomery County Council last week when the council approved $1 million in industrial bonds to help the firm pay for its new facility. The bonds are similar to tax-exempt municipal bonds, although the county bears no responsibility for repayment.

During recent years, Montgomery Couty has shown great interest in encouraging high level commercial and industrial development and expansion in the county, all of which helps generate large tax revenues for the county government.

The General Motors Corp. two months ago announced plans to locate a regional headquarters on five acres near the Shady Grove exit of I-270. County officials predict tax revenues of $50,000 from GM. But the new Digital complex could generate more than $100,000 in taxes after only the first part of the complex is built.

"When you're getting all excited about GM," said county development official Fred Agostino, "remember that's only 50,000 square feet. Digital (eventually could be) 40,000 square feet. Those kind don't come along every day."

Digital's Shaw said that when his company began looking for places to expand, the first choice was Montgomery, and the county development officials, including James Geigerich, head of the Office of Economic Development, were very cooperative.

"They showed something very important," Shaw said. "They wanted business in their county in a day and age when people are very anti-business . . . They welcomed us with open arms."

The company was formed in 1973 and has grown about 100 percent each year for the past two years, Shaw said.

Digital, which sells materials to the U.S. government, U.S. commerical interests, and 30 to 40 commerical interests in foreign countries, is now owned by Macom, Inc., an electronics company.