Scart Plugs... I don't get it..

Simple question that's been bugging my head for sometime.

Why does Scart pinout shows input and output?

You have composite input (pin 20) for sync and you got composite output (pin 19).

I don't get it, seriously. It must be one of those stupid detail stuff but I really don't get it.

It also works for out Left input and left ouput.... feel free to think I'm retarded but I don't get it.

 

Because one is an input and one is an output!

You do realize that those pins are cross-wired, right? You don't wire an input to an input.

 

I've never built a scart to scart plug.

When I build console cables I always use input for the final scart connector.

Example SNES:

Audio comes from the proprietary nintendo plug and goes to pins 2; 4 and 6. Labeled on every diagram audio input.
2: audio right input
4: audio ground
6: audio left input

It never worked out using the output pins which always made more sense but it never worked.

 

There is both input and output pins because SCART cables are bidirectional. This allows you to daisy chain multiple devices together to one SCART input on a display.

The pins aren't actually cross wired... I've tested the pins from the solder side to the connector side. Also, SCART cables that are meant for a one way use often don't even have the "output" pins wired.

 

Example: And why would a VGA cable not work on a daisy chain?

When you have on VGA pin 1 for red. It goes for female and male plugs and if you plug another cable it will still keep pin 1 as red.

So why would cross-wire improve anything?

 

It's so that you can have a device both receiving signal as well as sending signal concurrently.

 

Not challenging you or anything if that may sound rude but can you give me an actual use for it?

 

I think the main purpose was for VHS recorders and other recording devices. That way you could play VHS tapes on the TV, and you could also record TV programs onto VHS.

 

No offense taken - read the 'usage' portion of the Wikipedia article on SCART:

http://en.m.wikipedia.org/wiki/SCART

 

I finally understood why I got no sync with a few cables I build or why it worked without the cross-wire since I use scart switch boxes.

The box takes the sync input on pin 20 and delivers it to pin 19 (output) when I use the Pure AV scart - scart cable it already cross-wire it taking the pin 19 back to pin 20 and the next box keeps rolling the cycle.

And that's why my BNC adapter didn't worked. I was expecting sync on pin 20 and it's on pin 19 )))


I also need to fix pins 2 and 6 for audio to work. The correct pin here would be 1 and 3.

 

x

 

Yeah this wasn't making much sense to me because R G B pins don't follow this rule. It's only for composite and audio.

This also makes sense now for my switch boxes that the output can also be an input and switch between what is now my input. What I'm trying to say it's bi-directional boxes.

 

Correct me if I'm wrong here but I think you could also send RF into your VCR and then send the RF signal through scart to the TV as well. I think that was how VideoPlus worked as well.

(videoPlus btw for those not in the know, was a system which allowed you to enter codes into your VCR from your local printed TV guide, that code would trigger the VCR to start recording a show on a timer...I never got it to work correctly).

Oh how I miss those days.

 

No, VideoPlus worked on an algorithm that generates a code from date, time, channel and length. There's no broadcast. It's basically saying record this channel on this date at this time for this many minutes. You are probably thinking about PDC, which compensates for a delay in schedule... but all that did was send the information to the VCR via aerial to make the adjustments.

A VCR can in theory work as a pass-through for converting between signal types, yes.

 

Gotcha. Shoulda checked my theory first I remember at the time though I found it quite cool.

 

I believe the bidirectional nature of SCART allowed for overlays to be done as well. Video from device A passes through device B which slaps on an overlay which then gets output to your TV.

 

Primary goal of SCART was to be an universal connector. It has pretty all possible signals available at that time. Input signals going to TV, output to VHS recorders, and so on.
Personally I hate design of connector itself, build quality is terrible, it's too big, and has too much unneeded things. But that's the only thing which has RGB, so we need it.

 

Yeah, as I recall, most VCRs would give you a confirmation screen, allowing you to change the time manually, anyway. So it was pretty handy. Before that, there was a barcode pen available with some VCRs, I think Panasonic, and the likes of Radio Times would print a barcode, which did much the same thing. I thought that was pretty cool!

Yes, a big feature of SCART was overlaying without having to mix two signals together and output one combined picture.

 

You mean like subtitles?

I always wondered if rumors I heard when I was a kid were true that s-video pal VCR were able to turn subtitles on and off.

 

No. It's for devices overlaying their own signals (usually channel number, volume, play etc.). It doesn't allow a second signal to be recorded to tape and differentiated.

Closed caption decoders were available in PAL, SECAM and NTSC, so there's nothing special about the PAL ones. It was a special device sold to deaf people, though.