SCART
SCART (from Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs) is a French-originated standard and associated 21-pin connector for connecting audio and video equipment to television sets. Also called Péritel (especially in France, where the SCART word is not normally used) and Euroconnector. SCART makes it easy to connect VCRs, DVD players, set-top boxes (Pay TV, analog or digital cable, terrestrial digital TV), home computers, gaming systems and other equipment to television sets with optimal quality.
Motivations and applications for SCART
Before SCART came, consumer TV sets did not offer a standardized way of inputting signals other than RF antenna ones, and even antenna connectors differed between countries. Assuming the connectors even existed, devices made by different companies could have different and incompatible standards. For example, a VHS VCR could output a composite video signal through a German-orginated DIN-style connector or through an American-originated RCA connector.
SCART attempts to make connecting video devices together much simpler, by providing one plug that contains all the necessary signals, and is standard across different manufacturers. SCART makes connecting such devices very simple, because one cable can connect any two SCART-compatible devices, and the connector is designed so that you cannot insert it incorrectly.
Devices with multiple SCART connectors can pass the signals unchanged when not active, which allows daisy-chaining of multiple signal sources into a single TV socket.
The aging SCART standard has a number of drawbacks from today's point of view: it cannot carry both S-Video and RGB signals at the same time (originally it couldn't carry S-Video at all, which is quite logical since S-Video came into widespread use many years after SCART). However, it is possible to output S-Video and RGB alternatively from a single SCART towards a TV, for example from an S-VHS + DVD combo player, and the TV set will adapt automatically if it understands SCART's S-Video extension. SCART cannot carry component video (Y-Cr-Cb) signals at all. 5.1 or higher surround sound formats, or any kind of digital picture or sound transmission are also outside SCART's capabilities for now. Note that carrying a 5.1 signal to the TV set is of little interest, as such a signal is only usefully directed towards a surround sound system, and European TV programs do not offer 5.1 sound (some European satellite tv channels offers Dolby Digital 5.1 and 2.0 from early 2004). RGB signals, which were SCART's strong point for many years, are getting less useful today, now that the comparable (and, except for video game console use, slightly superior) component video signal format has been introduced. It also turns out that with the recent introduction of DVD and digital video RGB gained quality advantage again, and is probably the best way to enjoy the high resolution and high color separation contained in those new video sources.
Pin-out, (*) marking an extension to the original standard:
+------------------------------------------+
| 1 3 5 7 9 11 13 15 17 19 | 21
| \
| 2 4 6 8 10 12 14 16 18 20 \
+--------------------------------------------+
- AUDIO Output Right
- AUDIO Input Right
- AUDIO Output Left
- AUDIO Ground
- BLUE Ground
- AUDIO Input Left
- BLUE
- Function Switching
- GREEN Ground
- D²B Input
- GREEN
- D²B Output
- RED/(*)Chroma Ground
- D²B Ground
- RED/Chroma
- Blanking
- VIDEO/Sync/(*)Luminance Ground
- Blanking Ground
- VIDEO/Sync/(*)Luminance Output
- VIDEO/Sync/(*)Luminance Input
- Common Ground (IEC standard for a serial communication bus. It is a multi-master bus for home automation, and was originally developed by Philips in the 1970s.
Speculations about the intentions of the creators of SCART
The original purpose of SCART, according to some, was to prevent foreign television imports. Previously France had legislation which prevented all imported televisions, if they didn't support the old French 819 line monochrome system. One could understand that this effectively stopped any foreign televisions being imported, but when the 819 line system disappeared (its VHF frequency band was given to Canal Plus, the first French Pay TV network, at the beginning of the eighties) this was no longer a valid reason for banning imports. Therefore they introduced the SCART socket to try to maintain their private television market [another speculation], the newly passed legislation requiring every TV sold in France since 1980 to have a SCART socket. This was of course much less of a deterrent, as it was much easier for manufacturers to add a SCART socket to their televisions than to produce dual-standard sets, and the SCART was actually useful elsewhere, with the development of home video recorders and especially of video games and home computers, which could be very easily connected to TV sets, giving the best possible image quality.
Another alleged reason was Minitel. Early prototypes did not have their own display; instead, they used the TV as their display, similar to what game consoles did (and still do). An RF interface would have provided lesser quality text (true). Originally, there were supposed to be many models of Minitel. In the end, only one major model shipped, and had a built-in small monochrome CRT. So it is difficult to argue with the no-import rationale above.
See also
