Maryland's counties and municipalities, reeling from a recent Supreme Court decision that threatens to disrupt their control over cable television, are asking the state legislature to allow them to continue granting exclusive monopolies to cable firms without the specter of antitrust suits.

But the legislators are treading slowly in the complicated, high-technology world of cable television--a world that few of them fully understand--realizing that the implications of their decisions hold potentially far-reaching ramifications for the future of cable development and its impact in daily life.

For localities, the issue is simply one of home rule--a view supported by Gov. Harry Hughes--and the ability to regulate cable television in a somewhat orderly, though sometimes highly politicized, fashion.

The counties, which routinely award exclusive franchises for more mundane services such as garbage collection, thought they were immune to antitrust challenges. But the Supreme Court, in a Jan. 13 ruling, held that local jurisdictions could be sued under the Sherman Anti-Trust Act if they grant monopolies to cable firms without first getting authority from the state.

Without the authority, localities feel that cable firms losing out on the franchise can sue on antitrust grounds. "I see a lot of expensive litigation and perhaps delays," said Sally Lackey of the Maryland Municipal League. "The whole area is in a vast limbo."

But some legislators are uneasy about supporting monopoly over free enterprise in a lucrative business often tainted with political overtones.

John Hansman, Montgomery County's cable project manager, told legislators they need not fear, since the antitrust immunity extended only to the local home rule governments, and not to the cable firms.

The bill to allow exclusive franchises is being opposed by the Maryland-Delaware Cable Association, a group of area cable firms that says it would like to see the antitrust problems corrected at the federal level.

Sen. Victor L. Crawford (D-Montgomery), a lawyer with cable firm stock being held in a blind trust, said that until the law is passed, he is advising cable firms that lose out on local franchises to move into a county anyway and begin laying wires. "If they try to stop you, sue on antitrust grounds," he said. "It's free enterprise."

Most of the state's jurisdictions have opted to name a single firm as the exclusive beneficiary of the coveted franchises to lay wires and provide cable television to a certain number of households. Some counties, such as Prince George's, have divided their county into regions, awarding a single franchise in each region.

While most of the franchises do not specifically exclude other firms from building systems, the high cost of laying wires and ripping up streets usually prohibits competing firms from coming in without official sanction.