Ruth Taggart worried that her children, Christian, 12, and Justina, 16, watched too much television.
So last spring the Torrance, Calif., single parent bought TV Allowance, a device resembling a desktop calculator and costing about $100, that limits TV time to nine hours a week for each child.
Parents preset the machine, giving each child an access number and entering the number of hours of TV watching allowed. When time's up, the child's number won't turn on the set. The parent has an override code number.
"It works great," says Ms. Taggart. "I think the biggest result is that they think about something they really want to watch. They don't just turn it on to have noise in the house."
TV Allowance is one version of the TV blocking systems advocated recently by Rep. Edward J. Markey, D-Mass., chairman of the House telecommunications subcommittee, which held hearings on television violence.
Mr. Markey proposed legislation -- dubbed the "V-chip bill" -- that would require networks and cable broadcasters to show a "V" on the screen before a violent program starts; all new televisions would be equipped with a computer chip that when activated would black out the show when the "V" was broadcast.
In the bill, the television industry would establish criteria for rating TV violence. The chip costs less than $1 a set, Mr. Markey says. (All televisions are already equipped with similar technology since Congress required, effective in June, that sets contain a microprocessor to receive closed captioning for the deaf.)
Joseph N. Jackson, chairman of Protelcon, a small Los Angeles company, testified before the House subcommittee about his TeleCommander, a device he plans to manufacture.
"We decided to broaden areas of management for a parent," says Protelcon's president, Jim Brian. The TeleCommander will allow parents a number of choices in addition to limiting watching hours and blocking channels.
With the free-standing device, which looks like a cable box, parents can block out specific time frames and specific programs.
In another system, TV Guide on Screen of Denver is test-marketing a satellite system based on Motion Picture Association of America ratings. The software produces a list of upcoming shows on the subscriber's TV screen, and the parent can use the remote control to zap those they don't want their kids to see.
The system costs about $1 a month, says company president Bruce Davis.
The technology gives rise to other issues, however. Carole Lieberman, an assistant clinical professor of psychiatry at the University of California, Los Angeles, and chairwoman of the National Coalition on Television Violence, says she has reservations about the "V" chip because lawmakers or special-interest groups might gain control of ratings systems and attempt to censor ideas they didn't like.
She says ratings "need to be done with input from mental health professionals and people who have done research in violence in media. They should not be done by production companies making decisions by the seat of their pants, decisions designed to lose the fewest viewers."
And Gary Shapiro, group vice president of the Electronic Industries Association, a Washington trade group, has another reservation: Congressman Markey's proposal, he says, "presumes that parents are smarter than their kids technologically -- that parents have to put this code in there and the kids can't figure it out. But I have yet to talk to anyone who is smarter than their kids technologically."