By Cassimir Medford

Comcast confirmed Friday that it is testing the real-world reliability of switched digital video, a TV service delivery technique that could delay the need for heavy expenditure on overall network upgrades.

The technology promises to breathe new life into the cable operator’s fiber-optic/copper hybrid networks. Those networks are beginning to wilt under the immense bandwidth demands of HDTV.

Comcast, the largest cable TV operator in the United States, is at least the second major cable carrier to test the technology. Shares of Comcast fell $0.10 to $43.39 in recent trading.

United States

Cablevision, the fifth largest cable operator in the U.S., said this week it has successfully completed the biggest-ever deployment of switched digital video in the country. The rollout occurred in the New York area.

New York

The testing and deployment of switched digital video is extremely good news for a small clique of privately held firms such as BroadLogic, of San Jose, California, and BigBand Networks, of Redwood City, California.

BigBand’s life as a private company is on life support since the six-year-old company filed for an IPO in December.

BigBand, which is in a quiet period, counts nine of the top 10 largest cable operators as its customers. The company provided the key pieces of technology in Cablevision’s deployment of switched video.

Analog to Digital Switch

In November, BroadLogic said it began marketing a video processor technology that promises to triple cable operators’ network capacity. The company’s TeraPIX technology increases the bandwidth to the home by digitizing the video streams (see BroadLogic Boosts Cable).

BroadLogic Boosts Cable

Analog transmission eats up 500 megahertz of a typical 750 MHz connection, while digital transmission makes much more effective use of bandwidth. By freeing up bandwidth, cable operators can better serve their HDTV customers.

Cablevision announced nine international packages on foreign language channels that will be delivered via its switching technology. The channels will be presented in Spanish, Russian, Italian, Chinese, Korean, Hindi, and other languages.

With BigBand’s switched broadcast system, only digital TV programs currently being requested by customers will be delivered on the network.

In the current state of the art, all programs are sent to all homes on the network simultaneously even if no one is watching a majority of the programs. In the switched system, only programs that are being watched will be sent, freeing up bandwidth.

Comcast is currently testing switching technology in two undisclosed markets. The carrier said it plans to implement the technology later this year, but refused to disclose which vendor’s technology is being used.