SCART

SCART is a European standard for connectors of audio and video devices such as TVs and VCRs. Other designations are Euro -AV, Euro Connector, peritelevision connection (DIN EN 50049-1 ) and France Péritel. In the U.S. and Japan SCART is not used and only fitted in export devices. The abbreviation stands for SCART French Syndicat des Constructeurs d' Appareils Radiorécepteurs et Téléviseurs, which translates Manufacturers Association (hearing ) radio receivers and television sets. In the literature it is often the spelling found Scart because the acronym usually regarded as the initial word and accordingly " Skart " is pronounced.

The properties of the SCART connection are standardized in DIN EN 50049-1. An extension of this point-to -point connection from one device to one (1) other on a bus ( for example, TV, VCR, satellite receiver to a continuous line ) represents AV.link dar.

Area of application

The SCART connector tried to simplify the connection of different video devices and to unify, because it contains all the necessary signals into a single, multi-pin connector and forms a cross-vendor standard. About SCART, the analogue waveforms RGB, CVBS and (also composite video or closely CVBS called with YUV color coding for PAL or YIQ color coding in NTSC (obsolete, now also YUV). ) - For newer devices - S-video transmitted with the same color coding as composite / CVBS, however, in contrast to two separate lines for Y, and C ( = UV or IQ). Some device manufacturers apply now a high-resolution direct "YUV component video signal output" (sometimes will take YUV also used YPbPr, which, although on the same principle -based ( color difference signals), but other coefficients therefore used & not compatible with YUV ); such is the SCART connector not standardized, so still proprietary. A YUV output over the three RGB lines shall be triggered / selected in the Device menu. Digital video and audio signals ( see HDMI or digital YCbCr) are not supported.

Mechanical Design

The asymmetric design provides a practical reverse polarity protection on the one hand ( the plug can not be used upside-down ). On the other hand, due to its simple mechanical design often malfunction in the signal path. Therefore, and also because of the lack of locking options against pulling out to SCART could never prevail in professional and broadcast applications. There are instead D -Sub, used for the switching signals for AV signals BNC connector. Some manufacturers of Scart connectors provide " luxury versions " of are those in which, for example, shed and / or gold-plated contacts in the carrier.

Quality differences

Since analog signals are transmitted in SCART cable, a bad cable can considerably reduce the image quality compared to a good, particularly for lengths over 3 to 5 m.

Cable Conveniently offered often have no internal coaxial cable and only one common ( outer) screen. Therefore, in particular, the sound is disturbed by the adjacent unshielded video lines, which in certain image content (such as text overlays ) can be noticed as a rattle itself.

Due to lack of shielding and improper insulation ( reflections) and the video signal is impaired, which can be felt by a lack of focus and washed out colors. Likewise, in the absence of or inadequate shielding the sensitivity to high-frequency radiation is reduced, so that there is video or audio interference by strong stations from the environment comes ( radio stations, amateur radio, etc.).

Without suitable insulating material ( dielectric) with matching characteristic impedance cables with individual screening are therefore not much better. The falls (for example, DVD player or digital receiver ) to particularly in digital signal source as this will provide a much better picture quality than, for example, a VHS video recorder.

Development

From about 1976 televisions were equipped with then new, energy-efficient switching power supplies. This design feature allowed for the first time a low-cost (compared to 50 -Hz transformers in early Grundig televisions with mains isolation ) effective electrical isolation of the TV chassis from the power supply. It can therefore be dangerous to Wi- ground ( earth) potential instead of the earlier 110 to 240 volts. Peripheral devices such as video recorders, video disc player or video games have now been able without additional complex measures, such as coupling transformers for galvanic isolation or a UHF modulator are connected by small-signal safe connection to a TV. At the same time also the coaxial antenna connector without coupling capacitors was connected directly to the tuner. In addition to a low-loss transmission of the video signal for the first time stereo audio signal transmission from your VCR or video disc player to the TV was possible.

In the international market, especially in Japan and the U.S., there were many proprietary connections that often prevented devices from different manufacturers could be interconnected. There were differences in the dimensions of the plug, as well as the electrical specifications of the signals. The SCART standard developed in France - For this reason, in Europe in 1978 - together with the plans for their own satellite television satellite TV. First TVs with SCART interface arrived in Germany and Austria in 1982 on the market. Direct precursor of Scart was the six-pin DIN connector, which transferred a composite video and stereo audio signal, but only in one direction. Due to the then rare power disconnection in television sets he received only modest distribution. The most common connection in commercial television and video segment was then (and remained so until the early 1990s), the high frequency connection via antenna cable in which the AV signal is modulated onto a built-in UHF auxiliary transmitter. From the early 2000s is a connection between video / DVD / HD recorder due to lack of free HF channels is no longer possible, so they have been completely replaced by SCART, component and HDMI ports. In America and Japan, however, SCART is almost unknown.

SCART, a protectionist development: The SCART connector was developed around 1978 in France to prevent imports of television sets from other countries. Originally, there were in France laws that only allowed the import of TV sets, when the special black and white standard was supported by 819 rows. Since this was only used in France, the producers were forced other countries to spend high development cost of supporting this standard, so that there was almost no import devices. However, as the 819 -line standard was no longer used in France, there was no plausible reasons for this import restriction. In their place had from around 1981 all televisions offered in France have a SCART socket. Since that meant only a small overhead for the manufacturer and the benefits were quickly recognized, it became the standard in inexpensive video recorders.

RGB video

The RGB signal in the SCART standard is inextricably linked with the planning for the early satellite TV satellite TV in the early 1980s, the color information should no longer there by quadraturmoduliertem color carrier PAL ( Phase Alternating Line, lines with alternating phase ), but according to the MAC method ( multiplex - analogue components, analog components in the time - division multiplexing ) in the scart cable are transmitted via separate RGB lines. As a relic of TV - SAT can also be considered that the RGB lines in the scart plug unlike any other (except for the data lines) are performed unidirectional ( an interactive TV program, so that a TV would have returned his picture on TV with satellite, was never planned).

After TV - SAT had failed, came ( and come to today) many scart cable on the market, in which not all pins are assigned, often will only transfer the composite video and the audio signal. Fully occupied cable are often provided with the marketing names " RGB cable " or " RGB video ". This is particularly interesting for video game consoles, as this also consoles, the color information for a different modulation method as PAL deliver (eg NTSC), can be connected to televisions. With DVD players and modern television receivers, the use of such a cable lead to an improvement in image quality because the transmission via composite of principle ( modulated color carrier instead of individual lines ), the signal deteriorates.

Since the RGB lines 7, 11 and 15 no pulses are sent with the frame sync (except for the so-called " Sync on Green" mode that can be enabled on some devices ), the receiver uses to synchronize in RGB mode ( ie, at -scale RGB switching voltage (pin 16 )) of the additional co-transmitted signal at the video input ( pin 20). In most cases there is not only the required sync pulses, but a full composite video signal to be transmitted, so that even devices that can not accept RGB can work (especially video recorder), without any problems.

It is not possible to provide RGB and S-Video simultaneously available, since the latter has the pin 15 for the transfer of the separate color signal ( chrominance) " abused " is. Several devices transmit the chroma signal via pin 11 S was in the original video SCART standard ( yet) been provided, therefore, the connector has little to pole to provide for a separate line.

Pin Assignment

Wiring of SCART cables

Mindestbeschaltung

Vollbeschaltung

Fct Pin Pin Signal Cable Audio Out R 1 - Θ Θ ---------------- - 2 Audio In R Audio Out L 3 - Θ Θ ---------------- - 6 Audio In L Audio In R 2 - Θ ---------------- Θ - 1 Audio Out R Audio In L 6 - Θ Θ ---------------- - 3 Audio Out L Audio ground 4 - ---------------- - 4 Audio mass AV SWITCHG. 8 ---------------------- 8 AV switching ( aspect ratio) D ² B In / CLK? 10 ---------- ------------ 10 D ² B In or clock (CLK ) D ² B Out / DT? 12 ---------- ------------ 12 D ² B Out and Data (DT ) Digi. Mass 14 ---------- ------------ 14 Digi. mass RGB-B/YUV-V 7 - Θ Θ ---------------- - 7 RGB B / YUV V RGB -B Ground 5 - ---------------- - 5 RGB B mass RGB-G/YUV-Y 11 - Θ Θ ---------------- - 11 RGB -G / YUV Y RGB -G Ground 9 - ---------------- - 9 RGB -G mass RGB-R/YUV-U 15 - Θ Θ ---------------- - 15 RGB R / YUV U RGB mass R 13 - ---------------- - 13 RGB R mass RGB -S Blank 16 - Θ Θ ---------------- - 16 RGB Blank o RGB / CVBS Umschaltg. RGB -S mass 18 - ---------------- - 18 RGB -S mass CVBS In 20 - Θ Θ ---------------- - 19 Composite Video Out CVBS earth 17 - ---------------- - 17 CVBS earth CVBS Out 19 - Θ Θ ---------------- - 20 Composite Video In Shield 21 ---------- ------------ 21 cable shielding Explanations

Connection to the shield ( conductive) Θ individual screening criticism

The results from the standard construction details for the use of the plug, especially for frequent repositioning, lead to contact problems and damage:

The individual contacts are flat and thin, fixation inside the connector is via small tongues. This contacts can easily be bent or slip in the carrier to the rear.
The base plate remains on removal sometimes stuck in the socket.

The standard does not require fitting the sockets and connectors on the board or on the housing. Therefore, the easy breaking solder joints have to absorb forces acting on moving on plug and socket. Due to the generally angled cable guide, a little train or pressure on the right- rigid cable to one side to pry the plug from the socket; it comes in the wake to picture or no sound, which is not unique to the Scart connection can be assigned.

Norms and Standards

DIN EN 50049-1:1998 values for the small-signal connection between electronic devices for home use and similar applications: Peritelevison connection. German version of EN 50049-1:1997 A1: 1998. Published November 1998.
DIN EN 50157-1:1999-05 values for the small-signal connection between electronic devices for home use and similar applications: AV. link - Part 1: General; German version EN 50157-1:1998
DIN EN 50157-2-1:1999-05 values for the small-signal connection between electronic devices for home use and similar applications: AV.link - Part 2-1: Adjusting quality of signals and automatically selecting signal sources; German version EN 50157-2-1:1998
DIN EN 50157-2-2:1999-05 values for the small-signal connection between electronic devices for home use and similar applications: AV.link - Part 2-2: Basic system oriented commands; German version EN 50157-2-2:1998
DIN EN 50157-2-3:1999-05 values for the small-signal connection between electronic devices for home use and similar applications: AV.link - Part 2-3: System-oriented application; German version EN 50157-2-3:1998

Analogsignal Burst Fieldbus Baseband Luminance (relative)

92542