Norden Systems Inc., a wholly owned subsidiary of United Technologies Corp., has paid $4 million to take over American Computer and Electronics Corp. (ACE) of Gaithersburg, Norden officials said yesterday.

The acquisition essentially is a talent transfer that will give Norden 105 of ACE's 130 employes, most of whom are engineers who develop computer programs for military use.

Remaining ACE employes paid $600,000 to buy back about 15 percent of their former company, which they have renamed American Computer and Electronics Corp. International. The new company will produce commercial computer software for independent telephone companies, ACE President George Jimenez said yesterday.

"We will focus our activities on the telecommunications market. We expect to do about $2 million in business with about 30 employes this year," Jimenez said. ACE's annual sales were at $6.7 million at the time of its acquisition, which was formalized Monday night.

Jimenez called the takeover amicable. "Everybody thought it was a good deal," he said.

Norden is projecting $500 million in sales this year. The company "is interested in many of the same areas we were developing" in defense systems engineering, Jimenez said. "We have very bright, capable people who were doing that work. Norden offered them a larger, better capitalized environment for growth in their fields."

Norden, a major producer of military electronic equipment, needed a quick infusion of top-grade engineering talent to help keep up with growing defense demands for computerized weapons and radar systems, said Norden spokesman Paul W. Burton.

"We are growing very rapidly, and we need additional systems engineers, particularly the kinds of engineers who were working for ACE," Burton said. "It was good fortune for us to find a whole body of engineers like that."

Burton said Norden will keep its share of the former ACE operations in Maryland. Norden's Maryland wing will be headed by Paul Casner, a newly anointed Norden vice president.

At ACE Corp. International, Joseph Dorr has been elected vice president.