Cablevision Systems Corporation, founded in 1973, is an entertainment telecommunications services firm. The company's cable television business serves over 3 million households in New York. The firm also is known for its Interactive Optimum (iO) digital television, Optimum Online high-speed Internet, Optimum Voice voice-over-cable, and Optimum Lightpath fiber optic, SONET-based business communications services. iO (R) allows consumers to access third-party television programming, premium movie channels, on-demand movies, and digital music channels. The Optimum Online Web access cable service provides consumers with modem self-installation features. Cablevision Systems' Optimum Voice supports local and long distance calling across the United States, Puerto Rico, and Canada. The company's Optimum Lightpath fiber optic voice, data, Web, and video services are marketed to organizations across the health care, computer technology, financial services, and education sectors. Lightpath Interactive Healthcare Network telecommunications services support remote, real-time clinical diagnosis and treatment processes. Cablevision Systems' Rainbow Media Holdings LLC operates the Independent Film Channel (IFC), Women's Entertainment (WE), MetroChannels, MSG Network, News 12 Networks, and Fox Sports Net New York programming businesses. It also holds a 50 percent share of Fox Sports Net. iO's Mag Rack video-on-demand service, operated by Rainbow Media's Sterling Digital, provides consumers with lifestyle content. Cablevision Systems also owns and operates Madison Square Garden, Radio City Music Hall, and 54 Clearview Cinema movie theaters. The company owns the New York Knicks basketball, New York Rangers hockey, and New York Liberty women's basketball sports franchises. Cablevision Systems is listed on the New York Stock Exchange under the CVC symbol.