Dissatisfied with the speed at which television is going digital, the Federal Communications Commission voted Thursday to require television manufacturers to include digital tuners on all new sets by July 2007.

The requirement marks a significant step toward Congress' long-term goal of making high-definition TV, with its sharper images and better sound, standard viewing in American living rooms.

Commissioners voted 3-1 to require makers to include the tuners to all TV sets with screens of 36 inches and larger by July 2004, while the requirement for smaller sets would be phased in over the following three years. A group of manufacturers said they would appeal.

"This action will take these electronic appliances from being HDTV ready to HDTV reality," said Michael Powell, the commission's chairman.

Powell rejected industry complaints that the action would force consumers to pay as much as $250 more for a television set, saying the price of digital tuners would drop quickly as they are mass produced.

The dissenting vote came from Commissioner Kevin Martin, who noted that most TV viewers no longer receive their signals over the air, instead receiving cable or satellite television, and therefore don't need the digital tuners.

"I believe the cost of this particular proposal outweighs the benefits," Martin said.

After the meeting, Gary Shapiro, president of the Consumer Electronics Association, said only about 10 percent of American households receive their programming over the airwaves. The association calls the requirement a "TV tax" and says it would cost the industry and consumers about $7 billion.

"We believe the government should not tell consumers what to buy," Shapiro said. "We are going to court to oppose this."

Edward O. Fritts, president and chief executive officer of the National Association of Broadcasters, praised the ruling.

"Today's FCC decisions represent the most important action on digital television since adoption of the DTV standard in 1996," he said. "FCC Chairman Powell and the commission recognized the congressional imperative to stimulate the DTV marketplace, and deserve enormous credit for taking pro-consumer steps to jump-start the transition."

Transition from analog to digital technology has been delayed by reluctance within all parts of the industry to make the switch before most households can receive digital signals. The switchover requires expensive changes by broadcasters, cable companies, and local TV stations, as well as the manufacturers.

Commissioner Kathleen Abernathy said the TV set requirement was necessary to move the switch to digital TV forward. Without the rule, "the transition remains stalled," she said. "There's no question in my mind."

Broadcasters, who need consumers to be able to receive their digital signals, support a requirement for the tuners. They call the manufacturers' cost estimates "outlandish and ridiculous."

"We don't think consumers will see any cost increase," said Dennis Wharton, a NAB spokesman. "The simpler you make it for consumers -- you build the features into the set -- the faster you get to consumer acceptance of this new technology."

He said digital tuners are especially important to give people access to digital broadcasts from local stations not carried by cable or satellite.

The broadcast industry says 455 television stations are now broadcasting digital signals in markets that include nearly 90 percent of the nation's TV households. But they say less than 1 percent of the 25 million sets sold each year have digital tuners.

Congress is requiring most broadcasters to convert by 2006 from existing analog technology to more efficient digital television, which allows much more programming and data to be transmitted over one channel. Broadcasters were given second TV channels for free to do so.

When the switch is complete, broadcasters must return their analog channels to the government for other uses, such as wireless telephones.

Digital TV development has stalled over a number of issues, including the limited availability of high-definition programming and the pricey equipment needed for viewers to see it.

Cable and satellite service providers also have balked at allocating additional space for digital programming, while local TV stations struggle with the cost of converting to digital signals.