Standard Color Code Charts

The Radio Manufacturers Association

In 1924, a group of prominent radio manufacturers formed the Associated Radio Manufacturers. This organization was designed to control the licensing of the large number of radio patents so that each member could have access to all the relevant patents necessary to build radio transmitters, antennas and receivers. In the same year, the organization changed its name to the Radio Manufacturers Association.

Since the organization of the Radio Corporation of America in 1919, David Sarnoff sought, as commercial manager, to consolidate the patent pool formed by merging the radio interests of General Electric and American Marconi. In 1920, American Telephone and Telegraph acquired a million shares of RCA stock in exchange for its radio patents including rights to the Audion, Lee the Forest's invention. In 1921, Westinghouse Electric joined the consortium and brought along the Edwin Armstrong regeneration and superheterodyne patents and the Reginald Fessenden patents. This consolidation and standardization of radio technology allowed the RMA to control the essential technology aspiring radio manufacturers would need to supply the sudden public appetite for radio which, during the early part of the 20's, was growing rapidly. It also allowed RCA and other RMA patent owners to litigate against infringers from a strong, consolidated position.

One of the benefits of this control was the ability to standardize the manufacture of electronic parts. This allowed manufacturers to make parts which could be used by radio producers interchangeably. The organization also lobbied the nascent FCC to standardize the all important frequency allocations, something Sarnoff thought essential to further his ideas for the "Radio Music Box". This technical standardization would later allow the rapid development of a practical television system. In 1929, the RMA established a television committee to study the existing systems to define a common transmission standard. In 1936, the FCC suggested that the member companies adopt a common set of standards, which the FCC would consider. The organization also provided part number standards for electron tubes and semiconductors (JEDEC).

In 1950, the organization changed its name to the Radio Television Manufacturers Association (RTMA), then to the Radio Electronics Televison Manufacturers Association (RETMA), in 1953. In 1957, the name became the Electronics Industries Association (EIA), now known as the Electronic Industries Alliance. Still quite active as a standards agency, among other things, the EIA maintains an Internet website at

RETMA Color Codes

Field Coil Speaker & Plug Wiring

3 Wire Single Ended 3 Wire Single Ended

4 Wire Single Ended 4 Wire Single Ended

4 Pin Push-Pull 4 Pin Push-Pull

5 Pin Push-Pull 5 Pin Push-Pull

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