The short explanation
A rotary switch combines two functions in one control: turning moves through a list, pressing confirms. Paired with a small display it gives a compact device a complete interface without a row of buttons.
Where you run into it
It is the fallback that always works. No network, no browser, no app, no other device — just the unit in your hand. When a wrong network setting has made everything else unreachable, this is the way back.
It is also faster than a browser for the things you do most often: cycling through status pages to see what the link is doing takes two presses.
How the DR HDMI 8K handles it
On the DR HDMI 8K, up and down cycle the OLED info pages or move through the on-device menu, and a press confirms. Either direction also wakes the display from fade. Everything needed to recover a unit — switching DHCP back on, or a factory reset — is reachable from here without any network access.
Want to test your own HDMI chain?
The DR HDMI 8K is sold through the HDFury.eu web shop.