All Things EDID

EDID Overview

EDID is the thing that tells a computer what kind of thing it’s plugged in to. When you open up system prefs and it says “LG Ultra HD” that’s the monitor telling the computer “what” it is. EDID emulation is helpful for when you’re doing a lot of swapping of outputs or you turn your outputs off while leaving the computer on. Managing EDID is critical for installations because when some joker accidentally unplugs a projector, you won't get a display re-arrange.

On Mac systems, you need to use Headless/Passthroughs/Decimators to emulate EDID. You can also use an FX4 to keep EDID alive while the outputs are off.

On Windows systems, you need to use the same emulationd devices, unless you’ve got your own video cards that has EDID emulation via Software. Any P-series or A-series NVIDIA card allows you to save EDID to specific outputs. Adding a headless/pass to that chain will not work. Whereas, a decimator or FX4 will work. Bonus: capture EDIDs with this software and start building a library of them so that you can emulate performance easily.

Headless & Passthroughs

Headless, also called EDID Ghosts (Fubbi), allow you to trick a computer into thinking a display is plugged in, even if it isn’t. This prevents displays from being rearranged on restart or if a projector isn’t on. A regular Headless doesn’t have a passthru. Passthrus allow you to plug something into the EDID emulation. Passthroughs are preferred if you ever want to plug something in. They are more expensive than regular headless, but worth it in almost all situations.

Edge Case: If you need to mirror a display to a headless for some utility reason, then you don’t need a headless with passthrough (a headless without passthrough is just fine). There was a bug on the GPU of the old Mac Pro trashcans (ca. 2013), that was fixed if you threw a headless on the native HDMI port In general, headeless with passthrough are more useful and the difference in cost in nominal.

Types of Passthroughts: 4k60, Wux (1920x1200), 1080p60

They come in HDMI and DisplayPort flavors. I only own HDMI versions.

Decimators

These are custom EDID emulators - they are expensive swiss army knives that allow you to trick a computer into thinking it’s receiving whatever signal at whatever HZ. Incredibly useful. Highly recommended. Expensive.