After three years of development, RCA introduced by 1959[1] the all-transistor RCA 501, a medium- to large-scale computer which – according to the sales brochures – was "the world's most advanced electronic data processing system".
He also used color coding to assist the operator to run the machine in an "orderly and fully controlled manner" according to the advertisement.
Other customers included the US Navy and Army, State Farm Life Insurance, and General Tire and Rubber Company.
[2] A compatible version of the RCA 501 was sold by English Electric as their model KDP10/KDF8.
The RCA 501 utilized advanced manufacturing techniques such as pluggable card units or printed circuit boards.