Sept. 16 (Bloomberg) -- Paul Allen, the billionaire co- founder of Microsoft Corp., agreed to sell wireless airwaves he acquired in 2003 to a unit of AT&T Inc. for an undisclosed price, according to government filings.

The 24 wireless licenses cover spectrum in parts of Washington and Oregon, including the cities of Seattle and Portland, according to documents filed with the U.S. Federal Communications Commission. Allen holds the licenses through his Seattle-based Vulcan Spectrum LLC.

Allen has invested for years in technology to further his vision of a “wired world,” which also included the creation of St. Louis-based Charter Communications Inc., the nation’s fourth-biggest cable company. Charter filed for bankruptcy in March and Allen may have used the opportunity to unload his wireless license holdings, said Jim Wiesenberg, a principal at wireless spectrum consulting firm WW Associates.

“What Vulcan really had here is a play in the Pacific Northwest and presumably AT&T has given him an offer he couldn’t refuse,” said Scottsdale, Arizona-based Wiesenberg.

The filing didn’t include the sale price for the assets, which are being acquired by the carrier’s AT&T Mobility II LLC unit. David Postman, a spokesman for Allen, said he wouldn’t comment until the FCC approves the transaction.

AT&T fell 16 cents to $26.54 at 4 p.m. in New York Stock Exchange composite trading. The shares have dropped 6.9 percent this year.

C-Block

Michael Coe, a spokesman for AT&T, declined to comment on the financial terms of the transaction. The company is acquiring the spectrum to support the rollout of a fourth-generation wireless technology known as long-term evolution, or LTE, and to meet the demand for mobile services in the Northwest, he said.

The licenses cover the C-block segment of the airwaves within the 700 megahertz frequency, a portion of the spectrum previously reserved for ultra-high frequency, or UHF, television channels. This spectrum was freed up for wireless use when the U.S. government mandated that TV broadcasters switch to digital signals, effective this year.

Vulcan Spectrum also bought licenses in the A-block portion of the spectrum as a participant last year in an FCC airwave auction that raised almost $20 billion. Vulcan Spectrum’s A- block licenses, which also cover the Seattle and Portland areas, aren’t included in the proposed sale to AT&T.

To contact the reporter on this story: Miles Weiss in Washington at mweiss@bloomberg.net

Last Updated: September 16, 2009 16:02 EDT