Display dongles like these trick the PC into believing an actual display is connected to the display port.
The benefit depends totally on use.
It’s not magic; it just effectively “shorts” connections in the display port connector with either a resistor or two (for analog displays) or some kind of simple EPROM or IC (for digital displays) to make the port think an actual display is connected.
I am only familiar with it’s use as described here on Other World Computing’s website. I used one of these on a headless Mac mini server.
Without the adapter connected, I could only get specific (and small size) resolutions on my remote desktop session. But when I plugged in one of these things, it tricked the Mac mini into believing a larger, full resolution display was connected which allowed me to view things on a larger desktop.
This description from the Other World Computing page for this dongle explains it well:
“Remote accessing these machines used to mean being limited to viewing a hard to view, low resolution screen…even if you used an older monitor connected to the remote machine. With the NewerTech HDMI Headless 4K Display Emulator, you can now break free of limited 1024 x 768 or 1280 x 1024 resolution headaches when accessing macOS, Windows, and Linux machines remotely while viewing the desktop with up to full 4K 4096 x 2160 resolution.”
So when I used a dongle like this and remoted into the Mac mini that was being used as a server, the desktop display I would see on my Remote Desktop connection was larger.
And yes, a headless server technically doesn’t need a high resolution display. But in my experience, the GPU on a Mac mini doesn’t kick in unless some physical display — or this kind of dongle — is attached. Without the GPU rendering the display image, maneuvering around the desktop while remoted in is painful at best. Oftentimes you can literally see the screen redraw itself as you moved your mouse around or generally interacted with the desktop.
As further explained on the Other World Computing page for this dongle; bold emphasis is mine:
“But, trying to use those apps remotely on a headless machine running OSX 10.12.x (Sierra) and earlier can cause choppy images and mouse lags because the GPU isn’t activated in those OS versions. Plugging the NewerTech HDMI Headless 4K Display Emulator into an open HDMI interface on your machine is the solution to eliminate hampered performance and a small desktop.”
So using a dongle like this has a clear benefit for a headless PC.
But does this mean anything for a PC connecting to a so-called “dumb” TV? Unclear how a dongle like this would help.
As for the benefit of using it on a PC that is connected to a “dumb” TV? Unclear on what that would do. Maybe the idea is to force the dumb TV to have a higher resolution? Not too sure how that would work.
I believe the idea might be that if you connect a “dumb” TV to a PC, the display will only use safe (aka: low resolution) options to display an image on the screen. But somehow the assumption is if you plug this into the display port on your PC it will force the PC into using a higher resolution for the TV?
To me that would assume your PC has two display ports: One connected to the “dumb” TV and one with this dongle in it. And the GPU would then go, “Well, I guess I don’t know what this ‘dumb’ TV is, so I will default to the image on this other display that is connected; aka: the dongle.”
But that seems more like a “hunch” than a hard and fast rule. This kind of dongle is not a “one size fits all” thing. It is useful for very specific usage cases. It’s not magic.
