RCA connectors are a type of electrical connector commonly used to carry audio and video signals. Originally introduced by RCA in the early 1940s to connect pickups to radio-phonograph consoles, RCA connectors began replacing quarter inch phone connectors for consumer audio applications in the 1950s as component high fidelity systems became popular. While still used widely for audio/video, RCA connectors were designed simply for internal connections, with refinements added over time to remain compatible as applications expanded beyond their original purpose.

1. RCA connectors

2. An RCA connector, sometimes called a phono
connector or cinch connector, is a type of electrical
connector commonly used to carry audio and video signals.

3. The connectors are also sometimes casually referred to
as A/V jacks. The name "RCA" derives from the Radio
Corporation of America, which introduced the design by the
early 1940s for internal connection of the pickup to the
chassis in home radio-phonograph consoles.

4. It was originally a low-cost, simple design, intended only
for mating and disconnection when servicing the
console. Refinement came with later designs, although
they remained compatible.

5. RCA connectors began to replace the older quarter inch
phone connectors for many other applications in the
consumer audio world when component high
fidelity systems started becoming popular in the 1950s.

6. However, quarter inch phone connectors are still common
in professional audio, and miniature phone connectors
(3.5 mm) are predominant in personal stereo systems.

7. The connection's plug is called an RCA plug or phono
plug, for "phonograph." The name "phono plug" is
sometimes confused with a "phone plug" which may refer
to a quarter-inch "phone plug" (TS or TRS connector) or to a
connector used for a telephone.