Discovery Communications Inc., the Silver Spring-based group of cable television channels, said it is expanding to Virginia's Dulles technology corridor with a 100-person operation that will feed its channels to cable companies.

Discovery said it plans to turn a building in Sterling into a state-of-the-art center that compiles and transmits Discovery's 14 U.S. channels to cable operators around the country, said Marcos Obadia, executive vice president for media services. The center is scheduled to begin operations in the fall of 2005. The area offers the necessary fiber-optic infrastructure, Obadia said.

A spokesman declined to disclose the cost of the project, saying only it is a "multimillion-dollar investment."

Discovery now contracts with origination centers in Denver and Atlanta, where Discovery programs, commercials and promos arrive on videotape. The new center will be entirely digital and more automated. The television center will also house backup servers for Discovery's computer networks in Silver Spring.

The move is Discovery's latest effort to build up its technical infrastructure. About two years ago, the company, best known for its Discovery nonfiction channel, built a post-production facility in Silver Spring employing 400 people.

The new center marks Discovery's first foray into Northern Virginia. Montgomery County officials, who heaped praise on Discovery's decision to locate its headquarters in Silver Spring, said they were not miffed.

"We're always happy to have companies based in Montgomery County strengthen themselves," said Joe Shapiro, spokesman for the county's economic development office. "It's in our interest to have a strong Washington region. We're glad with the 1,500 jobs we have in Silver Spring."