stereo system used on analog television broadcasts in the United States and Canada (as opposed to the BBC-developed NICAM digital stereo sound system for analog television broadcasts, used in many places around the world.) Zenith was one of the first companies to introduce a digital HDTV system implementation, parts of which were included in the ATSC standard starting with the 1993 model Grand Alliance. They were also one of the first American manufacturers to market a home VCR, selling a Sony-built Betamax video recorder starting in 1977. The 1962 Illinois Manufacturers Directory (50th Anniversary edition) lists Zenith Radio Corporation as having 11,000 employees of which at least 6,460 were employed in seven Chicago plants. The corporate office was in plant number 1 located at 6001 West Dickens Avenue (north of the Chicago, Milwaukee, St. Paul and Pacific railroad tracks) where 2,500 workers made radio and television sets and Hi-Fi stereophonic phonographs. Plant number 2 was located at 1500 North Kostner Ave. where 2,100 employees made government electronics, radio and television components, transistors and hearing aids. Plant number 3 was located at 5801 West Dickens Ave. (also north of the Milwaukee Road tracks) where 300 employees made electronics and did servicing. Plant number 4 was located at 3501 West Potomac Ave. where 60 employees handled warehousing. Plant number 5 located at 6501 West Grand Ave. employed 500-600 workers who made government Hi-Fi equipment. A subsidiary of Zenith, the Rauland Corporation, located at 4245 North Knox Avenue, employed 850 workers who made television picture tubes. In the mid '60's Rauland produced the RCA 21" round color CRT, in 1965 it added a 21" rectangular 21" color CRT. In 1966, Rauland bought the Keebler cookie plant in Melrose Park, Illinois for production of color CRT's. Rauland's Niles, Illinois plant made flat-face radar picture tubes, night vision microchannel image tubes for the military and many specialty tubes. The other Zenith subsidiary in Chicago was Central Electronics, Incorporated located at 1247 West Belmont Ave. where 100 employees made amateur radio equipment and performed auditory training. Another Central Electronics plant was located at State Route 133 and Grandview in Paris, Illinois where 500 employees made radio receivers, with the total Zenith work force in Illinois being thus at least 6,960. In December, 1970, National Union Electric ("NUE") sued most of the Japanese television manufacturers for violation of the Anti-Dumping Act and a conspiracy which violated American