Prince George's Executive Parris Glendening, conceding that minority businesses may have been overlooked when the county's multimillion-dollar cable television contracts were let last fall, announced a voluntary plan yesterday to steer more cable business to minority firms.

The Glendening announcement came three weeks after the president of the local chapter of the Southern Christian Leadership Conference (SCLC) complained publicly that black firms were being excluded from the cable contracting process. Glendening, while acknowledging the SCLC complaint, said that he and Howard W. Stone Jr., executive director of the county's cable television commission, began working on the issue in January.

"There probably were some omissions during the franchising stage and contract stage," Glendening said. "We tried to address the problems that we saw," he added.

Unlike other goods and services purchased directly by the county, which require that at least 10 percent of the contracts go to minority firms, there are no minority participation goals in contracts with Storer Cable of Maryland or Metrovision of Prince George's County, holders of the exclusive franchises in the northern and southern parts of the county. Both cable firms have completed about one-third of the construction of their systems in the county, which are projected to cost $40 million each to build over three years, according to cable commission officials.

Storer, headed by former county executive Winfield Kelly, has let only one small contract to a minority-owned firm, with the bulk of its construction business going to three non-minority firms. Metrovision has awarded eight contracts, of which three have gone to minority firms. One of the minority-firm contracts was signed this week with a District Heights company, to provide electronic program material for broadcast over one of the cable channels. Another was for janitorial services and the third was for power-supply equipment, according to Metrovision General Manager Roger Wells.

Under the plan announced yesterday, the cable firms will provide Stone with information on contracts and subcontracts let to date as well as immediate and future contracts to be awarded. Stone will work with the Southern Maryland branch of the National Business League, a black business association, in locating area minority businesses capable of doing the work. The voluntary plan sets no goals or quotas for the minority share of future business.

Elois Hamilton, president of the county's SCLC chapter, said she would not be satisfied with a voluntary arrangement.