Tribune-United Cable of Montgomery County, stung by service complaints from hundreds of residential subscribers, has agreed to iron out major glitches in its fledgling television system and give homeowners access to a space-age information network.

The agreement with the county government, which officials were to announce today, includes a promise by Tribune-United to make available for the first time an inexpensive device that will enable viewers to record one cable program on a video recorder while watching a conventional show on their television.

The $5 electronic switch should go far toward easing the major consumer complaint heard by Tribune-United since it began wiring Montgomery County for cable last summer, said Michael Pohl, an officer in the New Jersey-based company that controls Tribune.

"It's a step towards better relations," said Pohl, vice president of Tribune Cable Communications.

Tribune-United also has promised to provide subscribers with a free "key pad" device that will enable them to call up a specific television channel rather than scroll through channels as most subscribers do now.

The agreement caps months of negotiation between the staffs of County Executive Charles W. Gilchrist, the County Council and Tribune-United, which has delivered cable television to roughly 10,000 county households and hopes to win at least 50,000 more by the end of this year.

Several county officials said yesterday that the Montgomery County government won concessions from Tribune-United only after threatening to file suit against the company to get it to live up to the terms of its 1983 franchise agreement.

Tribune-United officials downplayed that aspect of the talks yesterday, saying it made good business sense to placate subscribers and county officials.

"We're here to make money," Pohl said. "Montgomery County is unique because if subscribers have problems, they all call elected officials. We know what . . . we're doing. Trust us."

Since its debut last year, Tribune-United's system has received high marks in some Montgomery neighborhoods but has been criticized in others as unreliable and overpriced. Tribune-United officials said there was merit to some complaints, but they added that kinks should be expected in an evolving industry such as cable television.

In the first four months of this year, the company received 601 written complaints about its construction, installation and service programs. Of those complaints, 532 were settled, according to company records. There also were 67,619 telephone calls to the company, some of which were complaints.

A key component of the agreement, known legally as a memorandum of understanding, is a pledge by Tribune-United to make its planned business information network available to all residential subscribers.

The cable company originally intended to build a separate 440-mile cable system, known as I-NET, linking major institutions in the county such as high-tech firms, government agencies, hospitals and schools.

Under the terms of the new agreement, Tribune-United will limit its business network to roughly 50 miles and offer the broader I-NET system to regular home subscribers, officials said. Residents would need some computer equipment to participate.

Tribune-United also renewed its franchise pledge to put neighborhood switching stations in underground vaults in areas where all other utilities run underground.