It was classic Madison Avenue hard-sell, a presentation complete with colorful charts and earnestly delivered speeched laced with references to the firm's international reputation, its good intentions and the free enterprise system.

Executives of Arlington Telecommunications Corp. (ARTEC) were trying to sell the Arlington County Board on a plan to provide the company with "rate relief." The relief, officials argued, should come through a $2 increase in the monthly fees that 13,000 subscribing households pay for basic cable television service.

When the smoke cleared, the County Board had gone further then even ARTEC could have hoped. The board agreed to deregulate rates for the 27-chanel system, four months before wiring of the county is completed.

The hasty decision to deregulate the area's first countywide cable TV system will undoubtedly be viewed with interest in neighboring jurisdictions, where systems are planned or under construction.

For ARTEC, which is headed by former County Board chairman Thomas . Richards, deregulation means that rates are no longer subject to government control.

Board members contended that the "market place" would be the most effective regulator and that the county was not ready to get into the regulation field.

At the same time, however, the decision eliminates virtually the only leverage the county had over the incomplete cable system which began operating two years ago.

Officials of the $8 million system have yet to meet commitments made when they won the exclusive 10-year franchise in 1973. These include promises of a fully equipped production studio and classes for residents interested in producing programs.

No deadline for meeting those comitments appears in the franchise agreement. During last week's board meeting, ARTEC President Thomas W. Richards even hinted that those promises might be open to negotiation when he urged the board to "reexamine just what the public access requirements are."

ARTEC's pleas for "rate relief" may be justified, but the public will never know just how profitable the company is. ARTEC's chief operating officer, John D. Evans, told the board the company's books are closed because it is a private corporation.

County figures do show that ARTEC's gross revenues this year are expected to be $3.7 million, more than double that of last year.

Industry sources say that cable systems traditionally are expensive to start, fail to make money for about five years and then show substantial profits.

Programming is another concern. One subscriber recently said that ARTEC carries "too much God and too much basketball" and too little in the way of creative, alternative programming.

ARTEC offers only one hour a day of alternative children's programming. Half the channels in the system are Washington and Baltimore commercial stations. In addition, Evans told the board, "there is a 24-hour religious channel to meet the spiritual needs of our customers."

Evans failed to point out that the channel to which he refers is the Christian Broadcasting Network which scarcely meets the spiritual needs of anyone who isn't a fundamentalist Protestant.

Despite these shortcomings several board members said they believed that "the Arlington market place is the most efficient regulator."

That seems a curious argument since ARTEC is a monopoly.

Although cable technology is still in its infancy, several experts -- including former White House media aide Barry Jagoda -- predict that technological advances in this decade could make cable service as necessary to homeowners as telephone service.

To suggest, as franchise officials have, that subscribers can go elsewhere for services provided by an exclusive franchise is a little like telling consumers unhappy with Vepco to go elsewhere for electricity.

Perhaps the most serious question raised by deregulation is whether the county -- or consumers -- will have any say about ARTEC's product or operations.

Board member Dorothy T. Grotos cast the lone vote against deregulation after a parade of disgruntled subscribers urged the board to reject deregulation. Several testified that they had been unable to get a response from franchise officials despite as many as 20 letters and phone calls.

Board Chairman Walter L. Frankland, Jr. and board members Stephen H. Dtwiler and John W. Purdy said they failed to see any relationship between rate deregulation and ARTEC's alleged unresponsiveness. In general, the board seemed unusually eager to deregulate and thereby relinquish one of few controls the county possesses in the area of cable TV.

"The county is not ready . . . to retulate," said Purdy, who added that county officials "don't know the procedure" for regulation.

That rationale is not likely to please subscribers like Dennis Lucey. Lucey told the board he spent 18 months trying, unsuccessfully, to get Evans and other ARTEC official to return his phone calls or answer his letter regarding future service for his neighborhood.

ARTEC is "sitting on a gold mine and I say we should deny any increase until they get their act together," Lucey told the board. "What ARTEC needs is not rate relief but quick response to Arlington County."