Closed-Caption Decoders Becoming a TV Set Standard : Television: Law requires feature to help the deaf. Other audiences, too, can make use of subtitles.

BOSTON —  Most televisions manufactured after Wednesday for sale in the United States will have to have built-in circuitry for decoding closed captions for hearing-impaired viewers.

But the federally mandated change may have a far wider effect than originally intended. It may prove useful to patrons of noisy sports bars, those whose spouses are annoyed by the voice of “Tonight Show” host Jay Leno and children who are learning to read.

“I think there is going to be a tremendous audience outside of the deaf and hard-of-hearing community,” said Trish O’Connell, director of The Caption Center at WGBH-TV in Boston, a public television station.

WGBH was a pioneer in captioning programs, starting with a 1972 installment of “Julia Child, The French Chef.” The program was open-captioned, which meant everyone watching the show could see the captions.

With closed captions, developed about 10 years ago, text is broadcast but can be seen only on sets with special decoders that cost $180 to $200.

A law passed by Congress in 1990 requires that all TVs with screens 13 inches and larger, made in or imported to the United States, beginning this week must have built-in decoding devices.

With a push of a button, viewers using one of the new sets will be able to see the captions on their screens.

Cynthia Upson of the Washington-based Electronic Industries Assn. said the electronics will cost manufacturers an additional $5 to $20 a set, but TV makers may absorb some of the tab instead of passing it onto consumers.

“For us, this is the culmination of a 20-year dream, to allow deaf people to sit down with their parents and siblings and enjoy television,” said O’Connell, whose Caption Center provides captions for many network programs. Several competitors also are providing closed captioning.

Virtually all prime-time and news programs on the ABC, NBC, CBS, PBS and Fox networks are closed captioned, as are many movies released on videocassette.

O’Connell and Upson said that while the technology was developed to help the 24 million Americans with hearing difficulties enjoy television, it could serve other audiences, too.

Upson said closed captioning has helped some immigrants learn English, and some children and adults born in the United States to improve their reading skills.

Use of closed captions will increase further when it’s no longer necessary to buy an expensive decoder to receive them, she said.

For example, it will be helpful to fans in noisy sports bars and to those who want to watch TV while others are trying to sleep.