Audio/Connector/RCA
- A coaxial connector carrying one signal: a center pin for the signal, an outer shell for ground and shield. Every channel needs its own connector, so a stereo pair takes two and component video takes three.
- Also called a phono connector, after its first job of wiring a phonograph into a radio receiver, and cinch in France and Germany after the Chicago manufacturer of that name.
- Introduced by the Radio Corporation of America by 1937 inside the model U-109 radio-phonograph, and on the rear panels of its radios by 1938. Through the 1950s it displaced the 6.35 mm phone connector across consumer hi-fi.
- Never formally specified. Compatibility rests on manufacturers matching each other, which is why plug impedance varies and composite video over RCA matches 75 Ω only loosely.
Wirings
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