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|
 A male SCART connector (21-pin) | |||
| Type | Analogueaudio andvideo connector | ||
|---|---|---|---|
| Production history | |||
| Designer | CENELEC | ||
| Designed | 1976; 49 years ago (1976) | ||
| Superseded | RCA,DIN (in Europe) | ||
| Superseded by | HDMI,DisplayPort | ||
| General specifications | |||
| Audio signal | Bi-directional Stereo | ||
| Video signal | Composite (bi-directional), RGB (uni-directional), S-Video (sometimes bi-directional), or YPbPr (Component) | ||
| Pins | 21 (21 wires:RGB/10 wires:CVBS) 10 (10 wires:CVBS) | ||
| Data | |||
| Data signal | D²B andwidescreen switching | ||
| Pinout | |||
 | |||
| Female connector seen from the front | |||
| Pin 1 | Audio output (right) | ||
| Pin 2 | Audio input (right) | ||
| Pin 3 | Audio output (left/mono) | ||
| Pin 4 | Audio ground (pins 1, 2, 3 & 6 ground) | ||
| Pin 5 | RGB Blue ground (pin 7 ground) | ||
| Pin 6 | Audio input (left/mono) | ||
| Pin 7 | RGB Blue up S-Video C down[a] Component PB up[b] | ||
| Pin 8 | Status & Aspect Ratio up[c]
| ||
| Pin 9 | RGB Green ground (pin 11 ground) | ||
| Pin 10 | Clock / Data 2[d] Control bus (AV.link) | ||
| Pin 11 | RGB Green up Component Y up[b] | ||
| Pin 12 | Reserved / Data 1[d] | ||
| Pin 13 | RGB Red ground (pin 15 ground) | ||
| Pin 14 | Usually Data signal ground (pins 8, 10 & 12 ground) | ||
| Pin 15 | RGB Red up S-Video C up Component PR up[b] | ||
| Pin 16 | Blanking signal up
| ||
| Pin 17 | Composite video ground (pin 19 & 20 ground) | ||
| Pin 18 | Blanking signal ground (pin 16 ground) | ||
| Pin 19 | Composite video output S-Video Y output | ||
| Pin 20 | Composite video input S-Video Y input | ||
| Pin 21 | Shell/Chassis[e] | ||
output/input denotes symmetrical links | |||
SCART (also known asPéritel orPéritélévision, especially in France,21-pin EuroSCART in marketing bySharp in Asia,Euroconector in Spain,[1]EuroAV orEXT, orEIA Multiport in the United States, as anEIA interface) is a French-originated standard and associated 21-pin connector for connecting audio-visual (AV) equipment. The name SCART comes fromSyndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs, "Radio and Television Receiver Manufacturers' Association", the French organisation that created the connector in the mid-1970s. The related European standard EN 50049 was refined and published in 1978 byCENELEC, calling itpéritelevision, but it is commonly called by the abbreviationpéritel in French.
The signals carried by SCART include bothcomposite andRGB (with composite synchronisation)video,stereoaudio input/output and digital signalling. SCART is also capable of carrying S-Video signals, using the red pins for chroma.[2] A TV can be woken from standby mode and automatically switch to the appropriate AV channel when the SCART attached device is switched on. SCART was also used for high definition signals such as720p, 1080i,1080p withYPbPr connection by some manufacturers, but this usage is scarce due to the advent ofHDMI.[citation needed]
In Europe, SCART was the most common method of connecting AV equipment and was a standard connector for such devices; it was far less common elsewhere.
The official standard for SCART is CENELEC document number EN 50049–1. SCART is sometimes referred to as the IEC 933-1 standard.
Before SCART was introduced, TVs did not offer a standardised way of inputting signals other thanRF antenna connectors, and these differed between countries. Assuming other connectors even existed, devices made by various companies could have different and incompatible standards. For example, a domestic VCR could output a composite video signal through a German-originatedDIN-style connector, an American-originatedRCA connector, anSO239 connector or aBNC connector.
The SCART connector first appeared on TVs in 1977. It became compulsory on new TVs sold in France from January 1980,[3][4] and since 1987 in eastern Europe, such as Poland. The actual French legal decree was adopted on 7 February 1980 and revoked on 3 July 2015.[5]
The standard was subject to several amendments and at least 2 major revisions, approved by CENELEC on 13 November 1988 (EN 50049-1:1989) and 1 July 1997 (EN 50049-1:1997).[6]
The SCART system was intended to simplify connecting AV equipment (including TVs,VCRs,DVD players andgames consoles). To achieve this it gathered all of the analogue signal connections into a single cable with a unique connector, which normally made incorrect connections nearly impossible.
The signals carried by SCART include both composite and RGB (with composite synchronisation) video, stereo audio input/output and digital signalling. The standard was extended at the end of the 1980s to support the newS-Video signals. A TV can be awakened from standby mode, and it can automatically switch to appropriate AV channel, when the device attached to it through a SCART connector is turned on.
SCART is bi-directional regarding standard composite video and analogue audio. A TV will typically send the antenna audio and video signals to the SCART sockets all the time and watch for returned signals, to display and reproduce them. This allows "transparent" set-top boxes, without any tuner, which just "hook" and pre-process the TV signals. This feature is used for analogue pay TV likeCanal Plus and was used for decodingteletext.
A VCR will often have two SCART sockets, to connect it to the TV ("up", "primary" or "1"), and for video input from a set-top box or other device ("down", "secondary" or "2"). When idle or powered off, VCRs will usually forward the signals from the TV to the set-top decoder and send the processed result back to the TV. When a scrambled show is recorded, the VCR will drive the set-top box from its own tuner and send the unscrambled signals to the TV for viewing or simple recording control. Alternatively, the VCR could use the signals from the TV, in which case it would be inadvisable to change channels on the TV during the recording.
The "down" socket can also be used to connect other devices, such as DVD players or game consoles. As long as all devices have at least one "down" and "up" socket, this allows for connecting a virtually unlimited number of devices to a single SCART socket on the TV. While audio and video signals can travel both "up" to the TV and "down" to devices farther away from the TV, this is not true for RGB (and non-standard YPBPR) signals, which can only travel towards the TV.
"Down" and "up" are conventional. Logically, the TV is the last device of the "up" chain-path (stream) and the first device in the "down" chain path. Physically, the TV is under the device which sits on its top, hence the name "set-top box" for the device. Moreover, some sockets' relative position may enforce the belief that the TV is physically the last in the down direction.
Logically, the TV is on top and ends the "up" chain-path, translating the electrical info into an image and sound. From the same logical point of view the info stream, wherever it originates, may need processing such as decrypting (decoding, descrambling) or adding captioning/subtitles. In this case the info stream is sent logically "down" to dedicated function devices. From the last processing device the info stream is sent logically "up" to the TV, through all the chain-path. Another case is when the info stream is sent "down" and not expected to be sent back "up", for example when sent to a recorder.
Closing a loop on either the "up" or "down" chain-path may not have useful effects and may create instability.
As audio and (composite) video use the same pins on "down" and "up" connectors (and require a crosslinked cable), it is also possible to connect two devices directly to each other without paying attention to the type of the socket.
However, this no longer works when S-Video signals are used. As straight links (RGB red and blue up) were re-purposed to carry chrominance information, the S-Video pinouts are different for "down" and "up" SCART connectors.[7] Further, they are often not fully implemented.
Paying attention to the type of socket is essential when handling component RGB/YPBPR/S-video. Damage can be caused to devices incorrectly connected as follows:
Damaging pins 7, 11 or 15 may result in yellow, purple or blue/green images, due to the missing blue, green or red components respectively. When using S-video, damaging pin 7 or 15 may result in black-white images due to the missing chroma component ("down" and "up" respectively). Similarly, damaging pins 7 and 15 (PB and PR) while leaving pin 11 (Y) undamaged may result in black-white images when using YPBPR. Damaging more than one of these pins may result in combined effects.
SCART enables a device to command the TV to very quickly switch between signals, in order to create overlays in the image. In order to implementcaptioning orsubtitles, a SCART set-top box does not have to process and send back a complete new video signal, which would require full decoding and re-encoding of the color information, a signal-degrading and costly process, especially given the presence of different standards in Europe. The box can instead ask the TV to stop displaying the normal signal and display a signal it generates internally for selected image areas, withpixel-level granularity. This can also be driven by the use of a "transparent" color in a teletext page.
SCART allows a connected device to bring it in and out ofstandby mode or to switch it to the AV channel. A VCR or other playback device will optimally power on when a cassette is inserted, power on the TV (or switch it to video mode) and then start playing immediately if the cassette write protection tab is absent. When turned off, the VCR will ask the TV to power off, which it will do if it had been powered on by the VCR's request and if it remained in video mode. Only some TVs will do this—most only implement automatic switching to and from the SCART input.
The same signal can be used by asatellite receiver orset-top box to signal a VCR that it is supposed to start and stop recording ("pin 8 recording"). This configuration usually requires that the VCR be farther from the TV than the source, so the signal usually travels "down".
The cables for connecting equipment together have a male plug at each end. Some of the wires such as ground, data, switching and RGB connect to the identical pin number at each end. Others such as audio and video are swapped so that an output signal at one end of the cable connects to an input signal at the other end. The complete list of wires that are swapped are: pins 1 and 2, pins 3 and 6, pins 17 and 18, pins 19 and 20.
The original SCART specification provided for different cable (cordset) types denoted by a key color, but color-coding is rarely used and cables often use different, non-standard configurations.
| Type | Ring color | Pins | Description | Symmetric | |
|---|---|---|---|---|---|
| U | Universal | black | 1–20, 21 | Fully wired cable. | no |
| V | Video only | white | 17–20, 21 | Only composite wires. | yes |
| C | Combined | grey | 1–4, 6, 17–20, 21 | Composite Video and Audio | yes |
| A | Audio only | yellow | 1–4, 6, 21 | Audio | yes |
| B | Bus | green | 10, 12, 21 | Only data connections | Depends on protocol used |
Maximum SCART cable length is estimated to be about 10 to 15 metres without amplification.[citation needed]
Due to the relatively high signal voltages used in SCART, "hot plugging" (connecting or disconnecting devices while they are on) is not recommended. Although there is no risk of personal injury, there is the possibility of damaging electronics within the devices if the connector is inserted improperly.[citation needed] Also, since many TVs areClass II (double-insulated) rather than earthed, the large exposed shield on the SCART connector will be held at approximately half mains voltage if it is plugged into a powered TV with the other end unplugged. If the cable is then plugged into an earthed device with a metal case, inadvertent contact with the SCART cable shield while the earthed device is touched with the other hand can cause a painful electric shock. For this reason the device end of the cable should always be plugged in first and the TV end plugged in last.[8][9][10]
Quality differences exist in SCART cables. While a proper SCART cable uses miniaturecoaxial cables for the video signals, cheap SCART cables often use plain wires for all signals, resulting in a loss of image quality and greatly reducing the maximum cable length. A common problem on a cheap SCART cable is that a TV outputs a composite video signal from its internal tuner and this is induced orcrosstalked onto an incoming video signal due to inadequate or non-existent screening; the result is ghostly images or shimmering superimposed on the incoming signal. To non-destructively verify if a SCART cable uses coaxial cables, unscrew thestrain relief at the SCART connector and fold open the plastic shell.
Using higher-quality cables such as those with ribbon cords that have properly shielded coaxial cables inside might help in reducing a 'ghosting' effect, but it does not always eliminate it due to various factors. A more permanent method is to remove pin 19 (Video Out) from the SCART plug that is put into the TV, preventing a signal from being broadcast by the TV into the cable, so it cannot cross-talk with the incoming signal.
Two pins provide switching signals.
Pin 8, theswitch signal pin, carries a DC voltage from the source that indicates the type of video present.
Pin 16, theblanking signal pin, carries a signal from the source that indicates that the signal is either RGB or composite.
The original specification defined pin 16 as a high frequency (up to 3 MHz) signal that blanked the composite video. The RGB inputs were always active and the signal 'punches holes' in the composite video. This could be used to overlay subtitles from an externalTeletext decoder.
There is no switching signal to indicate S-Video. Some TVs can auto-detect the presence of the S-Video signal but more commonly the S-Video input needs to be manually selected. The same for the rare component YPbPr, which is in many cases implemented over a composite or RGB SCART.
The use of the data pins was not standardised in the original SCART specification, resulting in the use of several different protocols, both proprietary protocols and semi-proprietary protocols based on standards such asD²B.
Some of the most creative usages appeared in analogue satellite receivers. The function of decoding hybrid, time-compressed analogue-digital MAC transmissions into RGB and analogue audio was akin to making a digital receiver out of an analogue one. The D²B pins (10 and 12) were used for communicating withsatellite dish positioners and for driving magneticpolarisers, before these became incorporated intoLNBs. The daisy-chaining features were used to connect both a Pay TV decoder and a dish positioner/polariser to a singleDecoder socket on the receiver.[11]
CENELEC EN 50157-1 introducedAV.link as a standardised protocol to carry advanced control information between devices. It is a single-wire serial databus and allows carrying remote control information and to negotiate analogue signal types (e.g. RGB). AV.link is also known as nexTViewLink or trade names such as SmartLink, Q-Link or EasyLink. It appears as theConsumer Electronics Control channel in HDMI.
The data pins, 10, 12, 14, were used by some manufacturers forDolby Pro Logic, surround and multichannel on their TV sets (some high end models with built in Dolby decoders, and external surround speakers, both CRT, LCD and plasma sets, and only in Europe - and European versions of Japanese TV Sets and DVD players -, and mainly on S/PDIF), in order to connect a DVD player to the TV set and stream the Dolby and DTS to the surround of the TV set[citation needed]. However, this protocol was rarely used, as it was limited only to a certain manufacturer, and the connections were different from a manufacturer to another, and in some cases, it was only commanded by the pin 8. In this case, it was unusable with RCA to SCART adapters. Also, if a Compatible TV with such connection and a compatible DVD with such connection, but from different manufacturers were interconnected, the surround might not work, and only the stereo sound from the DVD player was available to the TV, because some manufacturers did not use SPDIF, but an own protocol. Also, this connection might be also lost, if the connection of the DVD with the TV was made indirectly (through a VCR in daisy chaining mode, for example), however, some VCR allowed the pass-through of these signals. Some DVD player manufacturers on some models offered SPDIF only on SCART, and an adapter in order to extract the digital audio signal to send it to a home cinema. To the present day this connection remains rare, as HDMI, S/PDIF, and TOSLINK can provide multichannel audio, also some TV sets with Surround built in may have an Optical or S/PDIF INPUT, beside Output[citation needed].
Nearly all modern DVD players and set-top boxes with SCART sockets can output RGB signal, which offers superior picture quality to composite signal. However, many devices do not have RGB output turned on by default, instead defaulting to composite video: RGB often has to be set up manually in the menu or via switches on the back of the device.[citation needed]
TheGameCube,Wii,Neo-Geo,Dreamcast,PlayStation,PlayStation 2,PlayStation 3,Xbox andXbox 360 can outputRGB,component video, S-Video, or composite video. These consoles come with the standard composite video connector, but the manufacturers and third parties sell connectors for component video hookup and for RGB SCART hookup. Where the Nintendo GameCube and Xbox automatically switch to the proper mode, the PlayStation 2 must be told via a selection in the system menu whether it is to use YPBPR or RGB video. RGB is only available onPAL region GameCube and Wii consoles, while S-Video is only available on NTSC consoles.[12]
Some older consoles such as theMaster System,Mega Drive/Genesis, andSuper Nintendo Entertainment System output RGB, and many older home computers (Amstrad CPC, laterZX Spectrum models,MSX,Amiga,Atari ST,BBC Micro andAcorn Archimedes, etc.) output RGB with composite sync suitable for SCART use, via DIN plugs. Standard-resolution arcade monitors use RGB signals with a composite sync, which is SCART-compatible.
Besides simple connection of external devices to SCART TVs, RGB SCART is used in theretrogaming scene for connecting vintage games consoles (including ones internally modified for RGB or 60 Hz RGB where necessary) to:
TheSAM Coupé microcomputer also uses a SCART connector for its output, however it is a non-standard pinout.[13]
There is also a Japanese version of the SCART connector, which is referred to as the Japanese RGB-21 connector, EIAJ TTC-003,[14] or simply JP-21. This version of SCART uses similar signals and the same connector, but it has a different pinout. In Japan and Korea, it is commonly called RGB-21 while it is more generally called JP-21 in the English-speaking world.
JP-21 was standardised in January 1983 with the norm TTC-0003[15] published byEIAJ, which was superseded in March 1993 by the norm CPR-1201[16] to include S-Video. CPR-1201 was withdrawn in March 2003 to be replaced by the equivalent norm CPR-1205, representing Japan's transition from analogue to digital, and thus antiquating analogue connectors.
It was adopted in Japan for the connector's ability to support RGB output format (no compression nor deterioration of original video signals) but, contrary to SCART in Europe, it never saw widespread use on the consumer market.
When using RGB video, the red channel uses the same pins in both standards, so red video with no audio is indicative of mismatching JP-21 SCART with EuroSCART.[17]
| Pin | Function | Pin | Function |
|---|---|---|---|
| 1 | Audio left channel input | 2 | Audio left channel output |
| 3 | Audio ground | 4 | Audio ground |
| 5 | Audio right channel input | 6 | Audio right channel output |
| 7 | Video ground | 8 | Video ground |
| 9 | CVBS input | 10 | CVBS output |
| 11 | AV control input | 12 | Ym input |
| 13 | Red signal ground | 14 | Ground |
| 15 | Red signal I/O | 16 | Ys input |
| 17 | Green signal ground | 18 | Blue signal ground |
| 19 | Green signal I/O | 20 | Blue signal I/O |
| 21 | Plug shield |
Notes:
As it was designed to carry analoguestandard-definition content, SCART is rarely used since the adoption ofHDMI, which carryhigh-definition content andmultichannel audio.
