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. 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. (See Origin, below.) 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.
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. However, quarter inch phone connectors are still common in professional audio, and miniature phone connectors (3.5 mm) are predominant in personal stereo systems.
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.
Read more about RCA Connector: Uses, Disadvantages, Origin, Phono Input, Color Coding in Consumer Equipment