Business highlights

Digital Equipment Corporation is planning to open a computer assembly plant in Mexico. A DEC spokesman says the plant will make MicroVAX II minicomputers for Mexican and Latin American markets at a leased facility 250 miles south of El Paso, Texas. The Mexican plant will also build cable and electrical harness assemblies to be shipped to Puerto Rico for inclusion in products for the United States market. Mexican law requires foreign-owned companies to export products made in Mexico in order to be permitted to sell articles there.

Lotus Development says a new version of its Symphony software has a serious defect that can wipe out data. Lotus says it will accept returns from dealers and will ship corrected versions next week. Lotus was scheduled to announce its newest program, Signal, a system that tracks the stock market, Tuesday. Sales of Jazz, its business software, and the company's stock price have dropped sharply in recent weeks.

Apple Computer Inc.'s board of directors is weighing action against chairman and co-founder Steven Jobs, who intends to hire away five of the company's managers to begin a new computer venture, according to reports published Tuesday. The San Francisco Chronicle said Apple president John Sculley and other senior executives were upset at Mr. Jobs's recent disclosure that he plans to hire the managers for an educational-computer company he intends to start. About four months ago, the board of the Cupertino, Calif., computermaker backed Mr. Sculley in a battle that took away Jobs's day-to-day management duties.

The United Press International branch of the Wire Service Guild has offered to buy UPI, either by itself or in partnership with one of several other prospective purchasers. Other bidders for the financially troubled wire service include an Indianapolis publisher, a Houston developer, and a former Central Intelligence Agency official.

The Guild unit, which represents 750 domestic UPI staff members, said earlier this week that it submitted an offer. It is unclear where the union's financing of the acquisition would come from. UPI is reorganizing under Chapter 11 of the federal bankruptcy act.

McDonald's Corporation has taken steps to avoid being gobbled up by merger-hungry corporations, although the fast-food giant says it knows of no plans for a hostile takeover. Fred L. Turner, chairman and chief executive of McDonald's, said the ``the current abusive takeover environment'' prompted McDonald's directors to adopt the measures Saturday.

The action follows several mergers and rumored takeovers involving food concerns. In recent months, R. J. Reynolds Industries Inc. acquired Nabisco Brands Inc., Nestl'e SA acquired Carnation Company, and Beatrice bought Esmark Inc.