William S Paley ( ) bought United Independent Broadcasters Inc, a group of 16 American radio stations, in 1928, changing name to Columbia Broadcasting System; became one of America's largest radio broadcasters, prime-time broadcasting ending in 1962; succesful experiments with colour television broadcasting began in 1939 but lost out to rival RCA system in 1953; only really began to expand television broadcasting in 1950s; in 1974 became CBS Inc; Westinghouse Electric Corporation acquired the network in 1995, changing name to CBS Corporation; acquired by Viacom communications conglomerate in 2000; CBS split off again from Viacom in 2005.