Giants in the cable television industry are courting Montgomery County residents, with an eye on the valuable franchise that the county will award one company late this year.

Representatives of 10 companies -- many among the largest in the industry -- went before a Montgomery County Civic Federation meeting Monday night and described the array of services cable television could bring to the county, but tempered their remarks with caution.

"Seven years ago cable television was a bankrupt industry. We couldn't pay our bills. And the reason is that we didn't have any programs, just wires strung up," said Denis Grubb of United Cable Television Corp., a Denver-based firm with 380,000 subscribers throughout the country. "We have to be cautious and lower our expectations of what we want utilities to provide."

The company representatives described the possibilities of localities, and even individuals, within the county choosing or making their own programs; of using cable television for home security systems, and of taking college courses through cable television. "A sophisticated, dynamic county like Montgomery holds great promise for local programming," said Jane Lampmann of Viacom Cablevision of Maryland.

"There isn't a free lunch. Subscribers, in the end, are going to pay for this system," said John Hansman, the county's cable television project manager. "We will have to make choices and tradeoffs between higher rates and more services."

The county must first decide who will receive cable television. Because Montgomery County includes large tracts of rural land where homes are too far apart to make stringing cables financially feasible, the primary service area has been defined as having at least 30 dwelling units per road mile.

The primary service area covers about 50 to 60 percent of the county's land and at least 96 percent of the 215,000 households. The county estimates that close to 50 percent of the households would subscribe.

"The density I've proposed is a lower density than is typical," said Hansman. "Fifty units per mile is common, but we're proposing to use 30. Much of the lower density that would be served is a higher income area and more inclined to buy more services."

Parts of Poolesville and Damascus that have at least 30 dwelling units per road mile are included in the primary service area, although they may not have the same number of channels because their distance from the main body of service means they must be specially connected to the cable system.

Municipalities may join the county franchise, although Barnesville and Laytonsville would not quality for the primary service area under the density criteria. Gaithersburg already has its own cable system. Other areas may get cable television if housing density increases, or if residents can guarantee at least 18 subscribers per road mile. The public may testify on the proposed primary service area Feb. 3 at 7:30 p.m. in the County Office Building in Rockville.

"The county has looked forward to cable TV since 1972. We've spent a half million dollars studying it. Finally, the process is under way," said council member Neal Potter at another recent Civic Federation meeting.

The process got off to a disappointing start when only one company applied for the job as the county's cable TV consultant. After some consideration of whether to reopen bids or change qualification requirements that the consultant sever all business relationships with applicants for the franchise, the county decided to hire the sole applicant, Telecommunications Management Inc., a California-based firm.

"The requirements seemed like a good idea before we realized how few consultants there were," said Hansman. "But we did get a good and responsive firm so we did not readvertize."

A 15-member citizens advisory committee is at work on the request for proposals that the county will send out to cable television companies. The committee will evaluate the applications and recommend one company for the franchise.

The county has not yet begun to accept proposals, but expects from 8 to 12 companies to submit applications. One of those companies is expected to be selected by County Executive Charles W. Gilchrist and confirmed by the county council by the end of the year.

Members of the advisory committee are: D. Warren Donohue, Rockville attorney; George R. Borsari Jr., mayor of Glen Echo; David Cosson, Potomac attorney and former staff member of Federal Communications Commission; Susan diRende of Gilbert and diRende Video Productions in Burtonsville; Thomas E. Dooley, president of Eastern Video Systems Inc.; Albert Feiner, electronics engineer; Michael Grace, AFL-CIO public relations director; Marion Hayes Hull, director of telecommunications programs at the Booker T. Washington Foundation; Adolph J. Koenig, program officer with the federal Public Telecommunications Facilities Program; Jeffrey A. Krauss of M/A-COM Laboratories; Alex M. McKinney, vice president of Systems Research co.; Preston R. Padden, asistant general counsel of Metromedia Inc.; C. Alan Peyser of TDX Systems Inc.; Roald A. Schrack of the National Bureau of Standards, and Maria C. Siccardi, media instructor.