What Is an RCA Jack? (Definition)

RCA connections on the back of a stereo receiver
An RCA jack or RCA plug (also known as a phono connector) is commonly used to connect various components in a audio-video system. Manny Santos/EyeEm/Getty Images

If you've had an opportunity to set up a home audio system, there's a good chance you've used RCA cables to connect audio sources, receivers/amplifiers, and maybe even speakers together. The cables are often recognized as having separate, colored plugs to match corresponding RCA jacks – more formerly known as RCA connectors – on the back of the equipment. RCA jacks have been around for many decades and can still be found in plenty of modern audio/video devices.

Definition: An RCA jack (also known as an RCA plug or a phono connector) consists of a small, circular hole ringed with metal. When used in conjunction with an RCA cable, which features a male connector that mounts firmly into the jack, is becomes possible for analog or digital information to pass from the input source to the output destination.

Pronunciation: ahr•see•ey jak

Example: An RCA jack can often be used to connect the analog output of a DVD player to the analog inputs located on the rear side of a television. The red and white colors represent the right and left stereo audio channels, respectively. A yellow connection (composite cable) is used to deliver the video signal.

Discussion: The technology was developed by RCA, the Radio Corporation of America, to connect a record player to an amplifier. Today, RCA jacks are commonly found connecting various components in many audio-video systems.

Basic connections feature the simple red and white for right and left stereo channels. Yellow is used for composite video, while component video connections (typically colored green, blue, and red) can be found on more complex equipment. Surround sound stereo systems can feature additional colors for the separate speaker channels.

RCA jacks are even used for coaxial digital audio (colored orange) signals or antenna connections. Sometimes the RCA cables can found in conjunction with an S-video (higher video quality versus a yellow composite) plug end. Ports are typically labeled to avoid color confusion. If audio equipment is turned on, one may encounter a buzzing sound as the cable end plugs into the RCA jack. This is due to the signal connection being made before the ground connection, hence why it's recommended to turn everything off before handling the cables.

Although new forms of input/output connections have been developed (e.g. HDMI, optical, coaxial digital), RCA jacks are still widely available. They exist in many audio/video sources, such as CD players, DVD players, VCRs, digital media players, turntables, video cameras/camcorders, game console systems (e.g. Microsoft XBox, Sony PlayStation, Nintendo's Wii) and more. And they allow the enjoyment of content through receivers, amplifiers, speakers, TVs, media centers, and even high-end sound cards for desktop computers. Why do we still use RCA jacks? The simple answer is likely a combination of ease of use, low-cost of manufacturing, reliability, and global acceptance.