Proposed - Retro System Video Standard (RSVS)

[syboxez]

Proposed - Retro System Video Standard (RSVS)
Version: 0.3 (2017/06/21)
NOT FINAL



Mini-DIN 9 connector:
1 - Blue
2 - +5v
3 - Green
4 - Y/Luma
5 - CSync
6 - Chroma
7 - Red
8 - Audio Left
9 - Audio Right
Shield - GND

All video and sync signals must be 75 Ohm compliant. Any TTL level signals are strictly prohibited. Required Vpp levels for each signal are identical to that of the SCART standard. All sync signals must be negative polarity.

Any cable using this standard must be direct wired, with no extra components inside the cable or either end of said cable. All devices using this proposed standard must have all components necessary for compliance internally. The only exception to this rule is converting the Y/C (S-Video) signal to CVBS (composite video).

All cables must use male ends, and all systems must use female connectors.

Outer shield must be grounded when using either connector.

Any system using this standard must support a 15KHz video signal (50Hz or 60Hz). Higher resolutions are allowed, so long as the system defaults to 15KHz.

Required signals: RGB video signals, CSync, Left and Right Audio, and +5v
- If only mono audio is available, then mono audio must be connected to both left and right audio pins.
- If CSync is not available, then a sync stripper outputting a 75 Ohm compliant signal must be added internally with the output going to the CSync pin. This is due to some displays requiring a clean sync signal to function properly.

Suggestions are welcome.

[syboxez]

So I got the idea to attempt a universal video standard for retro systems after watching one of RetroRGB's roundups where Bob mentioned it as an idea.

I aimed to find connectors that weren't used for any other system as video connectors and that were cheaply available and not going away any time soon, but I couldn't find a compact connector with enough pins, so instead I cloned the Genesis 2 video pinout (save for mono audio which is now ground) for the smaller connector to prevent equipment damage if a Genesis 2 cable were to be plugged into a device following this standard or vice versa (even though Genesis 2 cables are not compliant with this standard due to them not using direct wiring). I think that DB25 (commonly used as a PC parallel port connector) matches these needs though, as I am unaware of any devices that use this as a video port.

With the extended port, I tried to account for every analog video type out there, along with +5v and +12v available for European TVs that require it for RGB detection and aspect ratio detection. Let me know if I'm missing anything.

I thought a compact port would be necessary for systems too small to fit a DB25 connector. I am thinking of replacing the compact connector with a female DB9 connector at the system end (commonly used as PC serial or a joystick port), but would like input first, as people may prefer a round connector. I specify female so people wouldn't confuse it with another joystick port.

[bobrocks95]

So what's the proposed usage? Is this for new products like switches?

[Guspaz]

I'm not a fan of mini-din connectors: they're really tough to get aligned if you're doing it blind or semi-blind, and it's very easy to damage the connector by bending the pins. A DB-9 connector would be much easier. That said, DB-25 is pretty nuts, I doubt many people would want something that big on their consoles. There are also many pins there that are either not useful for people doing RGB mods (like luma and chroma) or that just aren't connected. People who use SCART cables don't put SCART sockets on their consoles, for example.

There is an increasing trend towards modding consoles without cutting plastic (or with minimal cutting): this can often be done by re-using existing connections (such as wiring up RGB to an existing multi-out connector), while DB-25 is the opposite extreme, requiring a huge hole be cut.

[syboxez]

I'm not a fan of mini-din connectors: they're really tough to get aligned if you're doing it blind or semi-blind, and it's very easy to damage the connector by bending the pins. A DB-9 connector would be much easier. That said, DB-25 is pretty nuts, I doubt many people would want something that big on their consoles. There are also many pins there that are either not useful for people doing RGB mods (like luma and chroma) or that just aren't connected. People who use SCART cables don't put SCART sockets on their consoles, for example.

There is an increasing trend towards modding consoles without cutting plastic (or with minimal cutting): this can often be done by re-using existing connections (such as wiring up RGB to an existing multi-out connector), while DB-25 is the opposite extreme, requiring a huge hole be cut.

I also hate mini-DIN with a passion. I have messed up so many connectors when working with it. DB9 is an option, but I want a smaller round connector. If people don't want to drill holes, then what connector would even be feasible?

I intended most people to use the compact connector, and I just put the DB25 there to have every possible analog video signal in one connector. I do agree that it's a bit much though. I doubt most people would need YPbPr or S-Video, and especially not HSync and VSync, for example. There are also many different grounding connections on the DB25 port, where you could probably just get away with 1 GND for everything, or even 0 GND and using the outer shielding as GND like the Genesis 2 does. I do like the idea of having a dedicated GND pin in case someone forgets to ground the shielding.

My goal with this is for people to just be able to buy modded consoles and generic universal cables. The main problem with this is consoles that either already have RGB available, or consoles that have a connector that can support RGB (AV Famicom and SNES Mini as examples). I'd prefer a standard like this to replace connectors in the second case, where consoles don't support RGB already, and with consoles that don't have a connector supporting RGB to begin with as a universal sign that that console is modded and supports RGBS, and all you need is a simple cable that (if you already have other consoles with this standard) you probably already have.

I also have a big problem with cutting plastic, and would love these connectors to be drop in replacements, but I'm unsure if that's feasible. I wanted mini-DIN specifically because it can fit nearly anywhere and replace existing connectors either with a 3D printed part, or an existing RCA/S-Video jack quite well without cutting anything (frontloader NES as an example).

If you know of any 13+ pin universal (and cheap) connector that could not be confused with another video connector from another system, let me know. I don't know if one exists with the same footprint as mini-DIN.

[Unseen]

If people don't want to drill holes, then what connector would even be feasible?

Wifi with Miracast? It may result in complaints about lag though. ;)

I intended most people to use the compact connector, and I just put the DB25 there to have every possible analog video signal in one connector.

Hot about DB-26 (technically DA-26)? It's a three-pin-row version of the 15 D-Subminiature connector and unlike DB25 or DE9 it's not already in common use for other purposes. Availability of cables with the connectors isn't really a problem because you wouldn't want to send video+audio signals over a printer/serial cable without individually shielded wires anyway.

[syboxez]

If people don't want to drill holes, then what connector would even be feasible?

Wifi with Miracast? It may result in complaints about lag though.

The standard doesn't have to say anything about input lag

I intended most people to use the compact connector, and I just put the DB25 there to have every possible analog video signal in one connector.

Hot about DB-26 (technically DA-26)? It's a three-pin-row version of the 15 D-Subminiature connector and unlike DB25 or DE9 it's not already in common use for other purposes. Availability of cables with the connectors isn't really a problem because you wouldn't want to send video+audio signals over a printer/serial cable without individually shielded wires anyway.

DB26 seems like a much better option than DB25. I simply didn't know it existed. I'll revise the post with that instead.

That still leaves the issue with drilling holes however. I'm also not expecting for people to use printer cables on their TVs. I don't know of many TVs where they use DB25 as video connectors

Also made it so that if people hook up the extended connector backwards (as I have done in the past with several connectors...), that they won't be feeding voltage into something important. I do like how DSub 26 is asymmetrical though, which makes that less likely. I did originally want to put in a requirement to use mini-coax for the RGB and CSync lines, but I decided against it since that would make cables much more expensive. Maybe I can put in an optional shielding spec with a unique name that can only be used when the cabling meets that requirement.

On a seperate note, how would I go about preventing people who don't comply with the standard from using the name? I want the standard to be entirely royalty-free and open for anyone to use, but I also want the standard to be strict.

[Sumez]

1. Why do you need anything other than RGB for video?
2. What's wrong with SCART? Not saying scart plugs are great or anything, but it's an already existing standard that's extremely widespread, supported by all major consoles out of the box using standard cables, and supports all involved signals except from component (which is really just some sort of encoded RGB)

[Unseen]

DB26 seems like a much better option than DB25. I simply didn't know it existed.

There is also an even higher-density option that packs 19 pins into a DE9 shell, but the connectors are much harder to source and likely a bit expensive.

On a seperate note, how would I go about preventing people who don't comply with the standard from using the name?

Trademark the name, license it to people who want to use it under the condition of adhering to the standard, send lawyers when someone uses it without license or without standard compliance.

[kamiboy]

[Einzelherz]

Kamiboy bringing the truth this morning/afternoon.

[syboxez]

That comic was the first thing I thought about when making this.

The thing is that there aren't really many competing standards. It's not like people are going to start sticking full size SCART sockets in their consoles.

[Hoagtech]

That comic was the first thing I thought about when making this.

The thing is that there aren't really many competing standards. It's not like people are going to start sticking full size SCART sockets in their consoles.

I think it would be cool to imbed scart to hdmi scalers internally and have everything on a hdmi connector standard. We would be using hdmi switchers instead of banbridge scart selectors and would be seamlessly integrated with all modern hardware.

A low cost scaler that doesn't suck would have to exist first but still.

I'm pretty sure hdmi already won that battle a few years ago

[bobrocks95]

A low cost scaler that doesn't suck would have to exist first but still.

So it'll never happen

[citrus3000psi]

I don't get this thread really. Are we trying to add DB25/Mini dins to consoles or are we trying to get rid of the scart head?

Each console has its already set of connectors to use. Take the TG16 for example, putting a normal size DIN in place of the original makes the most sense. I would never cut a space out for a DB25.

[Guspaz]

The TG-16 already exposes RGB via an external connector, and while some people may not like the form factor of existing solutions, cutting a hole in the side or ripping out the original connectors doesn't make much sense to me (not unless you're dealing with the CD unit, which is kind of rare for the TG-16 specifically).

[citrus3000psi]

The TG-16 already exposes RGB via an external connector, and while some people may not like the form factor of existing solutions, cutting a hole in the side or ripping out the original connectors doesn't make much sense to me (not unless you're dealing with the CD unit, which is kind of rare for the TG-16 specifically).

I meant to say DUO-R / RX, not TG16.

I have modded a TG-16 where I installed a DIN connector as the same location found on a SuperGrafx. That way the supercdrom2 would still plug in.

[RGB0b]

I have a few opinions on all of this, as I've already spent a TON of time searching something like this and decided in the end, it's just not possible, based on the requirements. First, it has to be a common connector that'll be available for years. Second, it would ideally be a connector that already has shielded cables made for it, so we'd just need to customize the "out" end. Next, it should have enough pins for RGBs, Y/C and CVBS, as well as ground, voltage and audio. The Sega Saturn DIN has everything you'd need, but good luck finding it for purchase! It should also be round, to make it easier for people to install; You can just drill a hole instead of using other cutting tools...

...that being said, I REALLY hate to see consoles cut at all and would especially hate to see a HUGE hole cut for one of the big ports suggested in this thread. I've seen so many consoles covered in holes over the years from people updating their mods, adding new mods, etc. If an internal mod is done right, in most cases you can return it to stock if you ever wanted it to. Once plastic is cut, it's cut forever. Myself and a few other people are trying really hard to find creative ways to do these mods without cutting ANY plastic at all. My favorite way is to remove the RF adapter and solder a DIN8 port upside down on the board, using the RF hole to plug in the RGB cable. Alternatively, in the few cases where the RF hole isn't big enough, I'd just run a female DIN8 cable through the RF hole as a "pigtail". While that's not the "prettiest" look, I very much prefer that over hacking a hole in the side. Also, the DIN8 only supports RGB, but that's predominantly what I'm using anyway.

Many people disagree with me and have the attitude of "they made millions of these and it's my console, so I'll do what I want with it". While that's completely up to you, I hope more people go for the no-cut methods. I'll be posting pics soon of very creative ways to do some of these installs without cutting any plastic at all. My favorite is the crazy way someone came up with to mod a front-loading NES without cutting!

[Hoagtech]

In theory. You could have as large of a connector as you wanted with out cutting as long as you can connect the connector through a conduit lead.

some paint

[citrus3000psi]

I'm more about my consoles looking OEM while preforming the upgraded function I intend it to. If this requires cutting then so be it, but I'll never hack up a console. Unless a customer wants me to.

In theory. You could have as large of a connector as you wanted with out cutting as long as you can connect the connector through a conduit lead.
some paint

I wouldn't be able to handle a dongle coming out my console. I keep on my consoles on shelves looking nice. I pull them down when I want to play them. I used to try and keep everything hooked up but I found myself wondering why.

[RGB0b]

In theory. You could have as large of a connector as you wanted with out cutting as long as you can connect the connector through a conduit lead.

I actually considered doing that to my 2600 jr. I'd rather have that then a cut, but to each his own.

[Einzelherz]

I'd argue that you don't need composite video so a minidin 9 would work. Which is why I used that on my nesrgb. Well that and the non availability of minidin 10 parts.

Just use USB type C. Plenty o' pins!

[syboxez]

I'd argue that you don't need composite video so a minidin 9 would work. Which is why I used that on my nesrgb. Well that and the non availability of minidin 10 parts.

Just use USB type C. Plenty o' pins!

USB C wouldn't turn out so hot. Many people would be plugging it into their computers/phones. I was thinking about using mini DisplayPort, but that would result in the same problem. Not to mention something with pins that small would make both the console modding process and the cable making process much more difficult.

As for the first part though, I could substitute CVBS in the Mini DIN 9 connector for S-video (replacing CVBS and the dedicated GND pin), since S-video is fairly simple to convert to CVBS, and can be done inside the cable. Since S-Video to composite is a universal solution and all cables would still be interoperable with every console using the standard, I could make an exception to the no internal electronics rule.

In theory. You could have as large of a connector as you wanted with out cutting as long as you can connect the connector through a conduit lead.

some paint

I don't know how many users would accept a connector just hanging out of their consoles. While I do that with some of my consoles to avoid cutting plastic, I'd prefer a solution that everybody could be happy with, and I'm thinking Mini-DIN 9 fits quite well with that idea. It shouldn't be too difficult to replace an RCA jack (RF or composite, for example) with a Mini-DIN connector without making any cuts.

I think it would be cool to imbed scart to hdmi scalers internally and have everything on a hdmi connector standard. We would be using hdmi switchers instead of banbridge scart selectors and would be seamlessly integrated with all modern hardware.

A low cost scaler that doesn't suck would have to exist first but still.

I'm pretty sure hdmi already won that battle a few years ago

Not everyone uses digital displays. I for one will be using CRTs for everything until all of them die.

[Hoagtech]

I'd argue that you don't need composite video so a minidin 9 would work. Which is why I used that on my nesrgb. Well that and the non availability of minidin 10 parts.

Just use USB type C. Plenty o' pins!

USB C wouldn't turn out so hot. Many people would be plugging it into their computers/phones. I was thinking about using mini DisplayPort, but that would result in the same problem. Not to mention something with pins that small would make both the console modding process and the cable making process much more difficult.

As for the first part though, I could substitute CVBS in the Mini DIN 9 connector for S-video (replacing CVBS and the dedicated GND pin), since S-video is fairly simple to convert to CVBS, and can be done inside the cable. Since S-Video to composite is a universal solution and all cables would still be interoperable with every console using the standard, I could make an exception to the no internal electronics rule.

In theory. You could have as large of a connector as you wanted with out cutting as long as you can connect the connector through a conduit lead.

some paint

I don't know how many users would accept a connector just hanging out of their consoles. While I do that with some of my consoles to avoid cutting plastic, I'd prefer a solution that everybody could be happy with, and I'm thinking Mini-DIN 9 fits quite well with that idea. It shouldn't be too difficult to replace an RCA jack (RF or composite, for example) with a Mini-DIN connector without making any cuts.

I think it would be cool to imbed scart to hdmi scalers internally and have everything on a hdmi connector standard. We would be using hdmi switchers instead of banbridge scart selectors and would be seamlessly integrated with all modern hardware.

A low cost scaler that doesn't suck would have to exist first but still.

I'm pretty sure hdmi already won that battle a few years ago

Not everyone uses digital displays. I for one will be using CRTs for everything until all of them die.

Well I like it because it's reversible but I get it not wanting a dongle too.

I do agree with your CRT sentiment. I almost exclusively play all my games on a graphics CRT monitor.


Also in theory you could run your hdmi scaler through a DAC. I wonder what dac chip analogue Nt uses?

[syboxez]

Update - Removed the extended connector entirely, as it goes against the goal of not having to cut anything.
Also replaced CVBS with Y/C (shielding will be used as ground instead).

A couple of thoughts: I'd like to know the best (also cheap and easy) way to convert S-Video to CVBS. I've tried putting a small ceramic cap in series with chroma, then muxing that into luma, but it looks awful compared to native CVBS. I'd like to put something in the standard for anyone who would like CVBS.

I was also thinking of making Luma mandatory in case someone would plug in a Genesis 2 composite cable into it to see if the console worked. It would be black & white, but it would at least display something.

I was also considering making a sticker near the connector mandatory so people would know that the connector is not a Genesis 2 connector, but I'm not sure if requiring a sticker is a good idea.

Really my biggest problem with mini DIN 9 is the confusion with the Genesis 2 connector. I just really like the form factor because it is easy to replace an RF jack with it without cutting any plastic.

[Guspaz]

USB C wouldn't turn out so hot. Many people would be plugging it into their computers/phones.

USB-C was specifically designed to support carrying any other protocol of which it knows nothing, with alternate mode giving over a negotiated number of other pins to a random other electrical signal. This is how USB-C is being used for DisplayPort, MHL, HDMI, and Thunderbolt 3, with companies being allowed to implement non-standard alternate mode extensions as they see fit for things like docks. This has caused some mess as different devices support different (or no) alternate modes, but it also means that being able to run arbitrary other signals over the cable/connector is baked right in to the standard.

Currently, analog video over USB-C is handled via DisplayPort with the normal DP->VGA conversion. I don't see any reason why you couldn't run analog signals over those pins in alternate mode, but it means you'd need a controller on either side to handle the connection orientation detection, muxing/switching (pins change based on orientation), and a USB PD controller to negotiate the alternate mode. With all that in place, you'd get something that is safe to plug in to random devices (and users are already kind of used to the whole "alternate modes are device-specific" thing), with effectively 11 usable pins: 8 pins from the reporposed data pins that alternate mode gives you, the sideband pin (which I think is not muxed and so is just duplicated on each side, so I'm counting it as one instead of two), power, and ground. Power and ground are actually four pins each, but I think they're all ganged together.

Anyhow, point is, theoretically possible, but the requirement of a full blown USB-C controller on each end of the cable makes it impractical.

[syboxez]

USB-C was specifically designed to support carrying any other protocol of which it knows nothing, with alternate mode giving over a negotiated number of other pins to a random other electrical signal. This is how USB-C is being used for DisplayPort, MHL, HDMI, and Thunderbolt 3, with companies being allowed to implement non-standard alternate mode extensions as they see fit for things like docks. This has caused some mess as different devices support different (or no) alternate modes, but it also means that being able to run arbitrary other signals over the cable/connector is baked right in to the standard.

Currently, analog video over USB-C is handled via DisplayPort with the normal DP->VGA conversion. I don't see any reason why you couldn't run analog signals over those pins in alternate mode, but it means you'd need a controller on either side to handle the connection orientation detection, muxing/switching (pins change based on orientation), and a USB PD controller to negotiate the alternate mode. With all that in place, you'd get something that is safe to plug in to random devices (and users are already kind of used to the whole "alternate modes are device-specific" thing), with effectively 11 usable pins: 8 pins from the reporposed data pins that alternate mode gives you, the sideband pin (which I think is not muxed and so is just duplicated on each side, so I'm counting it as one instead of two), power, and ground. Power and ground are actually four pins each, but I think they're all ganged together.

Anyhow, point is, theoretically possible, but the requirement of a full blown USB-C controller on each end of the cable makes it impractical.

Yeah. I was thinking of this being more along the lines of something that anyone could wire on their own cheaply and easily. Having to put a controller on each end of every cable would only increase costs when there are other solutions available.

If I were to simply use USB-C as a connector and wire GND and 5v as per the actual USB-C pinout, would anything be damaged if someone were to plug it in to a computer or a phone charger? That would still leave 8 pins to work with.

USB-C seems like a really good fit for replacing something like an RF channel switch or the RF RCA jack itself. Not to mention its durability and the fact that it is a reversible connector.

[Unseen]

power, and ground. Power and ground are actually four pins each, but I think they're all ganged together.

Why repurpose the power pins if you could use them to power the console instead?

[syboxez]

power, and ground. Power and ground are actually four pins each, but I think they're all ganged together.

Why repurpose the power pins if you could use them to power the console instead?

Would you not run into a problem with feeding 5v directly when the 7805 is still hooked up internally?

Also having power and video going through the same cable gives me 5200 flashbacks...

[Unseen]

Would you not run into a problem with feeding 5v directly when the 7805 is still hooked up internally?

You can request more than 5V with USB-PD