Is there a way to tell whether a caddy contains the right movie without actually loading the disc in a player?
All CED’s have a number printed on the raised center section of the disc that corresponds to either the number below the UPC (bar code) located on the rear of the caddy or to the stock number printed on the edge label of the caddy. The two numbers may not be exactly the same, but at least four consecutive digits will match up. Side 1 of all CED’s also has the UPC encoded as a series of concentric striations on the raised center section of the disc. RCA had machinery in the manufacturing plant that would simultaneously read this engraved UPC and the printed UPC on the caddy at the time of disc insertion to verify the correct disc was being placed in the caddy with the correct orientation.
