RCA connector
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An RCA jack, also referred to as a phono connector or CINCH/AV connector, is a type of electrical connector that is commonly used in the audio/video market. The name "RCA" derives from the Radio Corporation of America, which introduced the design by the early 1940s to allow phonograph players to be connected to amplifiers.
For many other applications it began to replace the older jack plugs used in the audio world when component high fidelity started becoming popular in the 1950s.
The corresponding plug is called an RCA plug or a phono plug, as opposed to a phone plug which refers to an audio jack plug.
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[edit] Uses
In the most normal usage, cables have a standard plug on each end, consisting of a central male connector, surrounded by a ring. The ring is often segmented for flexibility. Devices mount the jack, 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 connectors used ceramic).
As with many other connectors, the RCA has been adopted for other uses than originally intended, including as a power connector, an RF connector, and as a connector for loudspeaker cables. Its use as a connector for composite video signals is extremely common, but provides poor impedance matching. RCA connectors and cable are also commonly used to carry SPDIF-formatted digital audio, with plugs colored orange to differentiate them from other typical connections.
Connections are made by pushing the cable's plug into the jack 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 video, red for the right channel and white or black for the left channel of stereo audio. 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 camcorders and digital cameras. The male plug has a center pin which is 3.70 mm in diameter, and is surrounded by an outer shell which is 8.25 mm in diameter
[edit] Disadvantages
One problem with the RCA jack system is that each signal requires its own wire. Even in a simple case of attaching a cassette deck one may need four of them, two for input, two for output. In any common setup this quickly leads to cable spaghetti, which is made worse if one considers more complex signals like component video (another three cables each way). There have been numerous attempts to use combined connectors in both the audio and video world, but none of these have ever become universal—with the exception of the SCART connector, which has become very successful in Europe. For a time the 5-pin DIN plug was popular for bi-directional stereo connection between A/V equipment, but it has been entirely displaced by the phono connector on modern consumer devices, despite the fact that it takes four phono jacks to replace it. Nearly all modern TV sets, VCRs, and DVD players sold in Europe have SCART sockets, and in many cases they have no RCA sockets at all. However, RCA-to-SCART adapters are easily available, as SCART cables can also carry composite video and stereo audio, among other signals. For the purposes of consumer digital AV connections, HDMI is largely replacing RCA jacks as, like SCART, it has the ability to carry several different types of signals in the one connector.
[edit] Origin
The word phono is an abbreviation of the word phonograph, because this connector was originally created to allow the conction of a Phonograph turntable to a Radio Receiver, using the Radio as an amplifier. This setup was present in most radios manufactured in the 1930s onward by the Radio Corporation of America (RCA), who later marketed a special turntable for 45 RPM records.
[edit] Color coding in consumer equipment
Plugs and sockets on consumer equipment are conventionally color-coded to aid correct connections. The standard[1] colors for the various signals are shown below.
Note: sometimes black may substitute white.
| Analog audio | Left | White | |
| Right | Red | ||
| Center | Green | ||
| Left surround | Blue | ||
| Right surround | Gray | ||
| Left back surround | Brown | ||
| Right back surround | Tan | ||
| Subwoofer | Purple | ||
| Digital audio | S/PDIF | Orange | |
| Composite video | Yellow | ||
| Component video | Y | Green | |
| Pb | Blue | ||
| Pr | Red |
[edit] References
- ^ Consumer Electronics Association standard CEA-863-A "Connection Color Codes for Home Theater Systems"
[edit] See also
- ST connector is a type of fiber optic cable jack that looks similar to the RCA jack.
- High-end audio cables
| Audio and video connectors |
|---|
| Single conductor: Binding post | Banana plug | Fahnestock clip |
| Audio: RCA | Jack plug | XLR | DIN / Mini-DIN | BNC | DB25 | Speakon | TosLink |
| Video: DVI / Mini-DVI / UDI | RCA | VGA / Mini-VGA | DFP | BNC | DIN / Mini-DIN | 13W3 | D-Terminal | DisplayPort |
| Multi: ADC | P&D | HDMI | TRS | SCART | F | Belling-Lee | DisplayPort |
