AV:SCART

The SCART connector is named after the French industry union that invented it, but it also goes by plenty of other names including the official Peritelevision, Peritel, Euro AV, etc.

What
A fully featured SCART connector provides bidirectional composite video, two bidirectional audio channels, unidirectional RGBα, a "source active" status signal, and optionally an up to 2-pin data bus; at least one such connector was mandatory in France for most TVs designed between 1980 and 2015 but, while a truly common "European model" of TV did not exist in the mainstream until the large scale globalization of the 2000s due to fundamental differences, it eventually became a de facto standard in other CEE/EU countries as well, substituting national or even semiproprietary connectors such as DIN-based ones.

Additional sockets, if they exist, are not required to implement the full standard and indeed they rarely do: composite and stereo sound, often even without pin 8 source selection or the return path, are common.

Later versions of the standard also define an optional S-video extension, using video and red lines to deliver Y and C to the display (and video plus blue for the return path). As it cannot therefore be combined with RGB sources, there is often some means of mode selection; with mid-range 2-port displays, it is typical for the second port only to be switchable between composite and S-video. The revision also introduced the ability to reduce the voltage on pin 8 from 12 to 5 V to select a widescreen mode (to be implemented at the discretion of the TV).

Non-standard-resolution and YPbPr are not part of the specifications, although a few devices support them.

The data link feature found little application in the overall market, but it was the pride of certain brands and set the basis for the later and relatively more successful HDMI-CEC (which too was rebranded by pretty much every implementer).

The standard does allow for digital audio and video (as MAC, over the video pins) but this is yet another

Why (Not)
Many enthusiasts highly value the RGB capabilities for their quality advantages, but it must be noted that is not the primary purpose for their existence; rather, the intention of SCART is to reduce cost while improving interoperability between equipment, both in the individual home and the EU, hence the (mostly failed) provisions for tunerless pay TV decoders, video recorders, and teletext viewers (taking advantage of the ability to overlay their RGB graphics over the currently tuned channel).

In this latter example, and indeed even in standalone RGB operation, the signal is assumed to be genlocked (synced) to the currently displayed [RF/composite] source; most RGB cables for specific sources attempt to ensure this by providing an adequate source selection signal, but this may be ignored or manually overrode, resulting in an only technically synced picture. The transparency pin is indeed called fast blanking as it can be switched on or off in real time. As it turned out to offer little advantage, a few later TVs allow for disabling the overlay feature when a different source is selected.

Returning to the matter of RGB not being intended (though still usable as) a high quality substitute of the conventional video signal, in many designs the RGB data bypasses large parts of the video processor, resulting in a visible horizontal offset (due to the reduced lag compared to the sync) and the unavailability of YPbPr-based effects such as saturation and sharpness; some later models do convert it to YPbPr and provide an adjustable delay to more or less address these limitations. Where this is not the case, it's also common for the RGBα lines to be shared with the internal character generator (OSD/teletext), resulting in bright and poorly contrasted menus while displaying RGB; the flip side of this minor disadvantage is that many TVs which internally use SCART-compatible signals can have aftermarket RGB inputs fitted.

Again for the same reason, pin 16 is expected to be driven to approximately 1.8 V by the source to enable RGB mode, and only some later products allow for manually forcing RGB input. In fact, in a small number of early SCART (and non-SCART ) TVs, the AV input can only be selected by applying 12 V to pin 8!

Criticism of SCART primarily concerns the clumsiness and inadequate mechanical stability of the connector as well as the angled cable tending to obstruct other sockets, especially in the later but more common horizontal layout. A few consumers were also annoyed by the fact a simple visual inspection is often insufficient to determine the capabilities of a cable or port.

Console Scart Pinouts
See this site for Pinouts