Abstract :
The 500-type telephone set, first introduced on a field trial basis in selected areas of the United States in 1948, now will be available in eight different colors. Designed as a successor to the familiar 302-type combined set, the 500 type with its improved transmission, dialing, and ringing performance characteristics has been manufactured of black plastic in the Western Electric Company´s Indianapolis (Ind.) Works since 1950. To make the additional colors available to the subscriber has required months of concentrated research and study by both Bell Telephone Laboratories´ and Western Electric engineers.