WASHINGTON (AP) _ Jack Valenti defended the TV industry's proposed ratings system Thursday against complaints that it won't give parents enough information about shows' sex, violence and language. He also said the industry won't use any ratings system other than its own.

Valenti is overseeing the industry's effort to create a system to voluntarily rate entertainment programs on broadcast, cable and public television.

The six-tier, age-based system, similar to the one used for movies, will be unveiled next week and working by January, said Valenti, president of the Motion Picture Association. Each category carries a broad content description.

Child advocacy groups and other critics call this approach too vague. They called on the industry again Thursday to include specific warnings for violence, sex and language and the intensity of each in every show.

Sen. Joe Lieberman, D-Conn., held open the door to forcing the TV industry to adopt such a content-based system through legislation. If so, Valenti promised: ``We'll see him in court.''

Valenti asserted that the multi-layered ratings system favored by critics would make it harder for some 500 producers and other program originators to rate their shows uniformly. The information also would not fit neatly into the grids of newspaper and magazine TV listings, he said.

Critics rejected Valenti's assertions, contending the TV industry simply doesn't want to flag shows for specific violent, sexual and language content, fearing it may scare advertisers away.

``This is all money driven. It has nothing to do with the First Amendment integrity of Hollywood,'' said Rep. Edward Markey, D-Mass., who wrote a provision into law calling upon the industry to devise a ratings system.

Valenti, in turn, accused Markey of acting like a government ``Big Brother'' by trying to bully the industry to adopt a certain ratings system.

The ratings system is subject to Federal Communications Commission approval. If the FCC finds it unsuitable, it can move to appoint an independent advisory board that would create a new ratings system. But the TV industry isn't under any legal obligation to use it.

Under the TV industry's proposed system, shows would be rated by producers and program creators. It would be ``logistically impossible'' for parents to rate the more than 2,000 hours of TV shows aired each day, said Valenti.

Motion pictures are rated by an independent group, including parents. The group rates two movies a day, said Valenti.

Valenti said ratings could be appealed under the TV system, just as they are with movies. The 19-member TV appeals board would include six people each from the creative community, broadcasting and the cable industries and a chairman _ a spot he intends to hold for at least one year.

The industry will review the effectiveness of the system in its first year and could make changes in it then or any other time, Valenti said.

Under the TV proposal, shows would be rated using the following categories: ``K,'' material suitable for children of all ages; ``K-7,'' material suitable for children 7 and older; ``TV-G,'' material suitable for all audiences; ``TV-PG,'' parental guidance is suggested; ``TV-14,'' material may be inappropriate for children under 14; and ``TV-M,'' for mature audiences only.

A ``TV-PG'' rating would carry a description ``the program may contain infrequent coarse language, limited violence, some suggestive sexual dialogue and situations.''

The rating ``TV-14,'' would say programs may contain ``sophisticated themes, strong language and sexual content.'' The rating ``TV-M'' would say the program ``may contain profane language, graphic violence and explicit sexual content.''

A survey of 1,000 Americans released Thursday by the Media Studies Center of the Freedom Forum in New York concluded Americans prefer a content-based system over age by a margin of 73 percent to 15 percent.

The survey also found Americans split virtually down the middle on whether or not they would be likely to use the ``V-chip'' to block out objectionable programming. The margin of error is plus or minus 3 percentage points.