Federal regulators launched a broad review of media ownership rules Thursday that could lead to major changes for newspapers and radio and television stations.

The Federal Communications Commission voted 4-0 to begin reviewing a half-dozen rules to make them more consistent and able to survive legal challenges.

FCC Chairman Michael Powell called the examination "the most comprehensive undertaking in the area of media ownership in the commission's history.''

Powell said the agency had failed to keep up with changes in technology and the media marketplace. An overhaul of the rules "is long overdue,'' he said.

An appeals court rejected two rules this year and sent them back to the government. They involve restrictions on the national reach of companies that own multiple television stations and companies that want to own two television stations in the same market.

Two other rules to be examined concern the number of television and radio stations a company can own in one market and a ban on mergers between the four major television networks.

"The deeper you dig into our rules, the more confused you become,'' Commissioner Kathleen Abernathy said. "We have an obligation to reconcile our ownership rules.''

Added Commissioner Michael Copps, "I don't know of any issue before the commission that is more fraught with consequences for the American public.''

"At stake is how radio and television are going to look in the next generation and beyond,'' he said.

However, Copps warned that changes should be made "only if real evidence shows the public interest is served.''

The commission will seek comments from the industry and the public before drafting new rules. Copps said he wants to have hearings in Washington and across the country.

The FCC already is looking at a restriction that prohibits one company from owning a broadcast station and a newspaper in the same market, as well as a rule that limits radio station ownership.

The FCC has said its combined study and any potential changes to the rules are expected to be completed by spring.

Separately, the FCC planned to begin reviewing its policies on telemarketing, including whether to create a national "do not call'' list of people who do not want to receive sales calls.

The Federal Trade Commission has proposed such a list, but has limited authority to police certain industries — such as telephone companies — that fall under the FCC's jurisdiction.

Tribune Co. is among those seeking elimination of ownership restrictions since its acquisition of Times Mirror Co. gave it newspapers in cities where it already operates television stations — New York, Los Angeles and Hartford, Conn. Under current rules, the FCC could require the company to sell businesses when its broadcast licenses come up for renewal in about four years.

"These rules are antiquated and need to be changed,'' said Gary Weitman, a spokesman for Tribune, which owns 12 daily newspapers and 24 TV stations. Weitman said the growth of cable television and the Internet provides a diversity of media sources that was not available when many of the rules were crafted.

Some Senate Democrats, including Commerce Committee Chairman Ernest Hollings of South Carolina, oppose easing restrictions on media ownership, arguing that there is already too much concentration in the market for TV, radio and other services.

Consumer groups also oppose looser rules, saying that they will result in a wave of media mergers.

"To allow the most popular sources of news, information and entertainment to be owned by a small handful of people across the nation and in any one community is extremely dangerous for our democratic process,'' said Gene Kimmelman, co-director of Consumers Union in Washington.