An
RCA connector, sometimes called a
phono connector or
cinch connector, is a type of
electrical connectorAn electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...
commonly used to carry audio and video signals. The name "RCA" derives from the
Radio Corporation of AmericaRCA Corporation, founded as the Radio Corporation of America, was an American electronics company in existence from 1919 to 1986. The RCA trademark is currently owned by the French conglomerate Technicolor SA through RCA Trademark Management S.A., a company owned by Technicolor...
, which introduced the design by the early 1940s to allow mono
phonographThe phonograph record player, or gramophone is a device introduced in 1877 that has had continued common use for reproducing sound recordings, although when first developed, the phonograph was used to both record and reproduce sounds...
players to be connected to amplifiers.
They began to replace the older
TRS connectorA TRS connector is a common family of connector typically used for analog signals including audio. It is cylindrical in shape, typically with three contacts, although sometimes with two or four . It is also called an audio jack, phone jack, phone plug, and jack plug...
s (also called jack plugs) for many other applications in the audio world when component
high fidelityHigh fidelity—or hi-fi—reproduction is a term used by home stereo listeners and home audio enthusiasts to refer to high-quality reproduction of sound or images, to distinguish it from the poorer quality sound produced by inexpensive audio equipment...
systems started becoming popular in the 1950s. However, mini TRS connectors (3.5 mm jacks) and sub-miniature (2.5 mm) jacks are predominant in
personal stereoThe personal stereo is the term given to a portable audio player using an audiocassette player. This allows the listening of music through headphones while a person is mobile. The first personal stereo was the Stereobelt invented and patented by Andreas Pavel in 1977. Pavel attempted to...
systems.
The connection's plug is called an RCA
plugIn electronics and electrical assemblies, the term plug commonly refers to a movable connector, often, but not always, with the male electrical contact or pin, and is the "movable less fixed" connector of a connector pair...
or phono plug, for "phonograph". The name "phono plug" is sometimes confused with a "phone plug" which refers to anything from a
TRS connectorA TRS connector is a common family of connector typically used for analog signals including audio. It is cylindrical in shape, typically with three contacts, although sometimes with two or four . It is also called an audio jack, phone jack, phone plug, and jack plug...
plug to a
British phone plugBritish telephone sockets were introduced in their current plug and socket form on 19 November 1981 by British Telecom to allow subscribers to connect their own telephones...
to an RJ14
registered jackA registered jack is a standardized physical network interface — both jack construction and wiring pattern — for connecting telecommunications or data equipment to a service provided by a local exchange carrier or long distance carrier. The standard designs for these connectors and their wiring...
plug.
Uses
In the most normal usage, cables have a standard plug on each end, consisting of a central
male connectorIn electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female...
, surrounded by a ring. The ring is often segmented for flexibility. Devices mount the socket (
female jackIn electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female...
), consisting of a central hole with a ring of metal around it. The ring is slightly smaller in diameter and longer than the ring on the plug, allowing the plug's ring to fit tightly over it. The jack has a small area between the outer and inner rings which is filled with an insulator, typically plastic (very early versions, or those made for use as
RF connectorA coaxial RF connector is an electrical connector designed to work at radio frequencies in the multi-megahertz range.RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission...
s used ceramic).
As with many other connectors, the RCA has been adopted for other uses than originally intended, including as a
power connectorPower connector may refer to:* AC power plugs and sockets* Industrial power plug* DC connector* Blade connector, commonly found in cars for quick connection of wiring to electrical components* IEC 60309 , so-called "Commando" plug and socket...
, an
RF connectorA coaxial RF connector is an electrical connector designed to work at radio frequencies in the multi-megahertz range.RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission...
, and as a connector for
loudspeakerA loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
cables. Its use as a connector for composite video signals is extremely common, but provides poor
impedance matchingIn electronics, impedance matching is the practice of designing the input impedance of an electrical load to maximize the power transfer and/or minimize reflections from the load....
. RCA connectors and cable are also commonly used to carry
S/PDIFS/PDIF is a digital audio interconnect used in consumer audio equipment over relatively short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fiber optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high...
-formatted
digital audioDigital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...
, with plugs colored orange to differentiate them from other typical connections.
Connections are made by pushing the cable's plug into the
female jackIn electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female...
on the device. The signal-carrying pin protrudes from the plug, and often comes into contact with the socket before the grounded rings meet, resulting in loud hum or buzz if the audio components are powered while making connections. Continuous noise can occur if the plug partially falls out of the jack, breaking ground connection but not the signal. Some variants of the plug, especially cheaper versions, also give very poor grip and contact between the ground sheaths due to their lack of flexibility.
They are often color-coded, yellow for
composite videoComposite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
, red for the right channel, and white or black for the left channel of
stereo audioThe term Stereophonic, commonly called stereo, sound refers to any method of sound reproduction in which an attempt is made to create an illusion of directionality and audible perspective...
. This trio (or pair) of jacks can be found on the back of almost all audio and video equipment. At least one set is usually found on the front panel of modern TV sets, to facilitate connection of
camcorderA camcorder is an electronic device that combines a video camera and a video recorder into one unit. Equipment manufacturers do not seem to have strict guidelines for the term usage...
s (through 3.5mm Jack to 3 RCA, also called Mini RCA or miniature jack plug leads),
digital cameraA digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
s, and video gaming consoles. Although nearly all audio-visual connectors, including audio, composite and
component videoComponent video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
, and
S/PDIFS/PDIF is a digital audio interconnect used in consumer audio equipment over relatively short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fiber optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high...
audio can use identical 75 Ω cables, sales of special-purpose cables for each use have proliferated. Varying cable quality means that a cheap line-level audio cable might not successfully transfer component video or digital audio signals due to
impedanceElectrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...
mismatch and poor shielding quality (causing
signal-to-noise ratioSignal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power. A ratio higher than 1:1 indicates more signal than noise...
to be too low). Cables should meet the
S/PDIFS/PDIF is a digital audio interconnect used in consumer audio equipment over relatively short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fiber optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high...
specification as defined by the international standard IEC 60958-3 for assured performance.
The male plug has a center pin which is 3.175 mm (1/8 inch) in diameter, and is surrounded by an outer shell which is 8.25 mm (1/3 inch) in diameter.
Disadvantages
One problem with the RCA connector is that, when connecting the male into the female, the inner 'hot' (signal) connection is made before the 'cold' (screening) connection has been guaranteed. This often produces a loud buzz, and could possibly harm some equipment if it has not been switched off beforehand.
Another problem with the RCA connectors is that each signal requires its own plug. Even the simple case of attaching a cassette deck may need four of them, two for stereo input and two for stereo output. In any common setup this quickly leads to a mess of cables and confusion in how to connect them, which is made worse if one considers more complex signals like
component videoComponent video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
(a total of three for video and two for analog audio or one for digital coaxial audio).
There have been attempts to introduce combined audio/video connectors for direct signals but in the analog realm none of these have ever become universal, except in
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
where the
SCARTSCART is a French-originated standard and associated 21-pin connector for connecting audio-visual equipment together...
connector is very successful. For a time the 5-pin
DIN connectorA DIN connector is a connector that was originally standardized by the , the German national standards organization. There are DIN standards for a large number of different connectors, therefore the term "DIN connector" alone does not unambiguously identify any particular type of connector unless...
was popular for bi-directional stereo connection between A/V equipment, but it has been entirely displaced on modern consumer devices. Though
RF modulatorAn RF modulator is a device that takes a baseband input signal and outputs a radio frequency-modulated signal....
s inherently transmit combined A/V signals in video applications, they depend on broadcast television systems and
RF connectorA coaxial RF connector is an electrical connector designed to work at radio frequencies in the multi-megahertz range.RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission...
s which are not universal worldwide; RF signals are also generally inferior to direct signals due to protocol conversion and the RF limitations of the three major analog TV systems (
NTSCNTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
,
PALPAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
and
SECAMSECAM, also written SÉCAM , is an analog color television system first used in France....
).
Nearly all modern TV sets,
VCRsThe videocassette recorder , is a type of electro-mechanical device that uses removable videocassettes that contain magnetic tape for recording analog audio and analog video from broadcast television so that the images and sound can be played back at a more convenient time...
, and
DVDA DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
players sold in Europe have SCART connectors, though sometimes supplemented by RCA and/or RF connectors and there are also SCART-RCA
adapterAn adapter or adaptor is a person that adapts or a device that converts attributes of one device or system to those of an otherwise incompatible device or system.Some adapters may only affect physical attributes:...
s. Outside Europe, separate RCA connectors are usually used, supplemented by RF connectors for
backward compatibilityIn the context of telecommunications and computing, a device or technology is said to be backward or downward compatible if it can work with input generated by an older device...
and simplicity; though
mini-DIN connectorThe mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN is similar to the larger, older DIN connector...
s are sometimes used for
S-VideoSeparate Video, more commonly known as S-Video and Y/C, is often referred to by JVC as both an S-VHS connector and as Super Video. It is an analog video transmission scheme, in which video information is encoded on two channels: luma and chroma...
connections,
composite videoComposite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
,
component videoComponent video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
, and analog audio (
monoMonaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path...
or
stereoThe term Stereophonic, commonly called stereo, sound refers to any method of sound reproduction in which an attempt is made to create an illusion of directionality and audible perspective...
) all use RCA connectors unless RF is used. In the digital realm, however, combined A/V connectors are gaining ground;
HDMIHDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
is commonly being used today, and
DisplayPortDisplayPort is a digital display interface standard produced by the Video Electronics Standards Association . The specification defines a royalty-free digital interconnect for audio and video. The interface is primarily used to connect a video source to a display device such as a computer monitor...
is a potential competitor to HDMI.
For audio signals, an RCA connection is called
unbalancedBalanced audio is a method of interconnecting audio equipment using impedance-balanced lines. This type of connection is very important in sound recording and production because it allows for the use of long cables while reducing susceptibility to external noise.Balanced connections use...
, and a true balanced connection is generally preferred in certain applications because it allows for the use of long cables while reducing susceptibility to external noise.
Origin
The word
phono in
phono connector is an abbreviation of the word
phonographThe phonograph record player, or gramophone is a device introduced in 1877 that has had continued common use for reproducing sound recordings, although when first developed, the phonograph was used to both record and reproduce sounds...
, because this connector was originally created to allow the connection of a phonograph turntable to a radio receiver, utilizing the radio as an amplifier. This setup was present in most radios manufactured in the 1930s onward by the Radio Corporation of America (
RCARCA Corporation, founded as the Radio Corporation of America, was an American electronics company in existence from 1919 to 1986. The RCA trademark is currently owned by the French conglomerate Technicolor SA through RCA Trademark Management S.A., a company owned by Technicolor...
), who later marketed a special turntable for
45 RPMA gramophone record, commonly known as a phonograph record , vinyl record , or colloquially, a record, is an analog sound storage medium consisting of a flat disc with an inscribed, modulated spiral groove...
records, the model 9JY.
Phono input
A "phono input" is a set of input jacks, usually RCA jacks, located on the rear panel of a preamp, mixer or amplifier, especially on early
radio setsA radio receiver converts signals from a radio antenna to a usable form. It uses electronic filters to separate a wanted radio frequency signal from all other signals, the electronic amplifier increases the level suitable for further processing, and finally recovers the desired information through...
, to which a
phonographThe phonograph record player, or gramophone is a device introduced in 1877 that has had continued common use for reproducing sound recordings, although when first developed, the phonograph was used to both record and reproduce sounds...
or turntable is attached. Modern styli (phonograph needles) and
phono cartridgesA magnetic cartridge is a transducer used for the playback of gramophone records on a turntable or phonograph. It converts mechanical vibrational energy from a stylus riding in a spiral record groove into an electrical signal that is subsequently amplified and then converted back to sound by a...
give a very low level output signal of the order of a few millivolts which the circuitry amplifies and equalizes.
Phonograph recordings are made with high frequencies boosted and the low frequencies attenuated: during playback the frequency response changes are reversed. This reduces background noise, including clicks or pops, and also conserves the amount of physical space needed for each groove, by reducing the size of the larger low-frequency undulations. This is accomplished in the amplifier with a phono input that incorporates standardized
RIAA equalizationRIAA equalization is a specification for the correct recording of gramophone records, established by the Recording Industry Association of America...
circuitry.
In the 1980s, the phono input was widely available on consumer stereo equipment—even some larger
boomboxBoombox is a colloquial expression for a portable cassette or CD player. Other terms known are ghetto blaster, jambox, or radio-cassette. It is a device capable of receiving radio stations and playing recorded music , usually at relatively high volume...
es had them. By the 2000s only very sophisticated and expensive stereo receivers retained the phono input, since most users were expected to use digital music formats such as CD or satellite radio. Some newer low-cost turntables include built-in amplifiers to produce line-level (one volt) outputs; devices are available that perform this conversion for use with computers; or older amplifiers or radio receivers can be used. Nearly all
DJ mixerA DJ mixer is a type of audio mixing console used by disc jockeys.The key features that differentiate a DJ mixer from other types of audio mixers are the ability to redirect a non-playing source to headphones and the presence of a crossfader, which allows for an easier transition between two sources...
s have two or more phono inputs, together with two or more one-volt line inputs that also use RCA connectors.
This "phono input" designed for the millivolt signal from an unamplified turntable should not be confused with the modern standard one-volt line input and output that also uses RCA connectors and is found on video cameras, recorders and similar modern equipment.
Color coding in consumer equipment
Plugs and sockets on consumer equipment are conventionally color-coded to aid correct connections. The standard colors for the various signals are shown below; however, beyond 7.1 audio, there are no standardized colors as of yet.
In stereo audio applications there are combinations of either Black+Red,Grey+Red or White+Red RCA connectors; in both cases, Red denotes Right. White or Purple may also be replaced by Black. This is however not true in tape recorder applications with four connectors cables where white is always left channel recording and black or sometimes blue is always left channel playback. Four connector tape recorder cables is mainly used in adaptors between RCA connectors and
5-pin DIN connectorsA DIN connector is a connector that was originally standardized by the , the German national standards organization. There are DIN standards for a large number of different connectors, therefore the term "DIN connector" alone does not unambiguously identify any particular type of connector unless...
.
While these are the standard colors found on commercially made products, same-colored cables may also be used. For example, a red cable may be used instead of a yellow one, as there is no other difference between them. There are generally two kinds of cables, for video (composite, component YPbPr and RGB) and digital audio 75 ohm impedance coax cable is recommended, for analog audio high impedance cable is recommended. Using high impedance cable for video and digital audio signals degrades signal quality, more noticeable with longer cables and with higher video resolutions. Using a 75 ohm impedance coax cable for analog audio is usually technically not a problem (but those cables are usually more expensive than high impedance cables)
Composite analog videoComposite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
|
Composite |
Yellow |
|
| Analog audio |
Left/Mono (record if 4 connector tape cable) |
White |
|
| Right (record if 4 connector tape cable) |
Red |
|
| Left tape play if 4 connector tape cable |
Black |
|
| Right tape play if 4 connector tape cable |
Yellow |
|
| Center |
Green |
|
Left surroundSurround sound encompasses a range of techniques such as for enriching the sound reproduction quality of an audio source with audio channels reproduced via additional, discrete speakers. Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and...
|
Blue |
|
| Right surround |
Gray |
|
| Left back surround |
Brown |
|
| Right back surround |
Tan |
|
| Subwoofer |
Purple |
|
| Digital audio |
S/PDIF S/PDIF is a digital audio interconnect used in consumer audio equipment over relatively short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fiber optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high...
|
Orange |
|
| Component analog video (YPbPr ' is a color space used in video electronics, in particular in reference to component video cables. is the analog version of the YCBCR color space; the two are numerically equivalent, but YPBPR is designed for use in analog systems whereas YCBCR is intended for digital video. cables are also...
) |
Y |
Green |
|
| PB |
Blue |
|
| PR |
Red |
|
| Component analog video/VGA (RGB/HV) |
R |
Red |
|
| G |
Green |
|
| B |
Blue |
|
| H(Horizontal sync)/S(Composite Sync) |
Yellow |
|
| V(Vertical sync) |
White |
|
See also
- Line level
Line level is a term used to denote the strength of an audio signal used to transmit analog sound between audio components such as CD and DVD players, TVs, audio amplifiers, and mixing consoles, and sometimes MP3 players....
- Component video
Component video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
- High-end audio cables
- Jack connector
In electronics and electrical assemblies, the term jack commonly refers to a surface-mounted connector, often, but not always, with the female electrical contact or socket, and is the "more fixed" connector of a connector pair...
- RF connector
A coaxial RF connector is an electrical connector designed to work at radio frequencies in the multi-megahertz range.RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission...
- SCART
SCART is a French-originated standard and associated 21-pin connector for connecting audio-visual equipment together...
- XLR connector
The XLR connector is a style of electrical connector, primarily found on professional audio, video, and stage lighting equipment. The connectors are circular in design and have between 3 and 7 pins...