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Radio Corporation of America (RCA) jacks and plugs are found on some of the most commonly used varieties of radio frequency (RF) coaxial cables. A male RCA connector consists of a central contact pin and an outer sleeve, each of which can be crimped or soldered to a shielded wire within a cable. Multiple RCA cables are typically required for any given application, since each one can only carry a single audio or video signal. Three RCA cables are required for a system that has stereo audio and composite video, while five are needed for stereo audio with component video. Modern high definition video signals can be transmitted through analog RCA connectors, though digital signals require different solutions.
The RCA connector was invented in the 1940s and was first used to connect an amplifier to a phonograph. They are sometimes referred to as phono connectors due to this original purpose, even though they can be used to carry both audio and video from many different devices. By the 1950s, the RCA connector had largely replaced the tip ring sleeve (TRS) connector in most high fidelity audio systems, and they remained popular even after the introduction of digital audio and video. Most audio-visual equipment comes equipped with RCA connectors, and some speakers do as well.
There are two types of RCA connectors that are used together to make solid electrical connections. Female RCA connectors are typically located on devices. These connectors typically protrude from a device and have one contact on the exterior surface and another in the center. Male RCA connectors are typically found on cable ends and contain an outer sleeve contact in addition to a central pin connection. There are also numerous other configurations, such as extension cables that have one male and one female RCA connector, splitters that can connect a monaural output to a stereo input, and converters that include female RCA connectors and a male TRS connector.
Each audio or video signal requires a separate RCA connector and cable, so it is possible for systems to become very complex. Inputs, outputs and even RCA cables can be color coded to reduce confusion. A typical color scheme for RCA connectors has white and red referring to audio signals and yellow to composite video. White RCA connectors are typically used for the single audio channel in monaural systems as well, and various other colors are often used for surround sound systems. Composite video typically uses red, green and blue connectors, though some systems include yellow and white for horizontal and vertical sync.