Displays Passive DVI-D to VGA adapters (a mystery)

You often see these. I've used them as doorstops. They lack the four analog pins that would make DVI-I, and therefore have no obvious way to work.

Why do they exist?

This thread suggests they're simply a con, an ebay ploy to sell nonfunctioning, technically impossible bits of plastic for profit. My own experience doesn't line up with that, because I have - from way back in the day - genuine ATi-branded ones which clearly were made to work in a specific context.

I just can't fathom what it would be.

 

How much power would it take to run a video DAC? Because if I remember correctly; DVI-D does have a +5V line used for monitor sense and control in it.

Beyond that; DVI-D doesn't appear to have any analog data output paths on it to repurpose other pins into RGB Analog transmission.

 

Passive HDMI to Component/Composite RCA anyone? https://www.ebay.co.uk/p/5ft-HDMI-M...omponent-AV-Adapter-Cable-HDTV-HD/26007911132

I figure that if they are not just complete cons they are dumb copies of some device specific adapters that (by virtue of having full control over what does what) can do all sorts of analogue over digital oddness.

 

Well, that's no bloody use. I need an active HDMI to garden hose, goddammit!

 

That HAS to have been put together for 1 April?