Cablevision Systems Corp. said on Thursday it will have the capability to carry more than 500 channels of high definition television programming by year-end as competition mounts from satellite TV and telephone operators.

The New York-based cable operator also said it will add 15 new HD channels from Voom HD Networks starting June 26, amounting to a total of 40 HD programming services for Cablevision digital cable TV customers.

U.S. cable operators have been waging a marketing offensive against satellite TV operators in a bid to convince the public they will have the capability to deliver the most high definition channels.

Large flat-screen HD TVs have been one of the hottest selling consumer electronics segments in the United States for several years, prompting satellite and cable companies to vie for subscribers by touting the quality of HD video for their TVs.

Over the next few years, HD will move from a nice-to-have to must-have, said Craig Moffett, analyst at Bernstein Research.

The competition is even more intense in Cablevision's regions where phone companies Verizon Communications and AT&T Inc. are rolling out advanced digital TV services that are ready to carry HD services.

Satellite and phone company TV providers continue to talk about their plans for HD, but Cablevision is actually doing something about it, said John Trierweiler, Cablevision's senior vice president of product management.

DirecTV Group Inc., the leading U.S. satellite TV provider, has promised to offer as many as 150 HD channels by the end of the year. It is planning to launch a new satellite over the summer to increase its HD broadcast capacity.

Moffett said modern cable plants such as Cablevision's could offer virtually unlimited HD channels thanks to technology such as switched broadcast video. But sheer capacity does not mean there is enough television programming to fill available channels, whether on cable, satellite or via phone operators.

There's a big difference between HD channel slots and HD channels, said Moffett.

Comcast Corp., the No. 1 U.S. cable operator, said it will have around 400 HD 'choices' by the end of the year and as many as 800 by the end of 2008. Comcast spokespeople have explained HD 'choices' will include video- on-demand channels, as well as HD linear broadcast channels.

Voom, which is owned by Cablevision unit Rainbow Media, will provide Cablevision with specialist HD channels such as HDNews, Monsters HD, Gameplay HD and Kung Fu HD.

There will probably be something like 30 mainstream TV channels on any of the operators by the end of the year, Moffett said.

Cablevision shares were down 6 cents at $35.92 in afternoon trading on the New York Stock Exchange.

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