In a move that could advance the spread of broadband internet service nationwide, the Federal Communications Commission voted Nov. 4 to open up unused, unlicensed portions of the television airwaves known as "white spaces" to deliver wireless broadband service to more Americans.

The vote is a big victory for public-interest groups and technology companies such as Google Inc. and Microsoft Corp., which say white spaces could be used to bring broadband internet access to rural America and other underserved parts of the country.

"White spaces are the blank pages on which we which we will write our broadband future," said Jonathan Adelstein, one of two Democrats on the five-member commission. Adelstein added that white spaces could become a "third channel" to reach consumers beyond the telephone and cable networks that represent the primary competition in today's broadband market.

The vote came over the objections of the nation's big TV broadcasters, which argue that using the fallow spectrum to deliver wireless internet access could disrupt their over-the-air signals. Manufacturers and users of wireless microphones--including sports leagues, church leaders, performers, and even some educators--have also raised concerns about interference.

The next step for the main opponent, the National Association of Broadcasters (NAB), could be a lawsuit to stop the FCC's plan from taking effect. NAB had no immediate comment.

Four commissioners voted to approve the plan, with one commissioner--Republican Deborah Tate--dissenting in part. Among her concerns, Tate raised questions about how potential interference problems would be handled.

Last month, a technical report by FCC engineers concluded that interference could be eliminated with the use of wireless transmitter devices that rely on spectrum-sensing and "geolocation" technologies to detect nearby broadcast signals.

The FCC's plan will allow the use of white spaces to provide broadband following the transition from analog to digital TV broadcasting in February, which will free up additional wireless spectrum. That space also could be used for improved communications networks to connect police officers, firefighters, and other emergency responders.

Supporters of the plan say the vacant spaces between TV channels--which would be available for free, unlicensed use, as Wi-Fi now is--are particularly well-suited to providing broadband service, because they can penetrate walls, carry a great deal of data, and reach a wide geographic area. FCC Chairman Kevin Martin, one of three Republicans on the commission, called white spaces "a very valuable national asset."

Opening up this spectrum to high-speed wireless connections has been a high priority for internet companies, which stand to benefit as more Americans get online. Technology and equipment makers, meanwhile, are counting on a multibillion-dollar market for advanced wireless devices to transmit and receive signals--including laptops, personal digital assistants, and TV set-top boxes.