So, I just had the weirdest problem with a couple PowerBook G4s that I have NEVER even heard of before. Let me give you a bit of back story here before I go off on this tangent.. My main setup is my Mac Pro 5,1 using a 23" ADC Acrylic Cinema Display plugged into this KVM switch, along with a sawtooth G4 and two PCs. Well, as some of you may know Windows 10 loves to turn the brightness all the way down on this display with no way of turning it up again without using this. I had just finished a (failed) upgrade to Win 10 1903 on my 5,1 that kept BSOD'ing seconds after reaching the desktop (theres a thread on this in the Other OS section on here). Because of this, I was not able to brighten the display again because it had kept blue screening before I could open the brightness app. This is where the PowerBooks come in. The only way I've figured out how to change the brightness of an ADC display when this happens is to plug it into a PowerBook (for some reason the sawtooth doesn't give a brightness slider nor does the Mac Pro under Mac OS). Well, I plugged the DVI cable from the one of the machines using the KVM into a TiBook running leopard. It connects, then a few seconds later the PowerBook just shuts off like I removed its battery. WTF? I turn it back on. It does it again before it can even finish booting. I'm already annoyed enough at Windows failing and making my display nearly unreadable, so I grabbed another PowerBook, this time a 15" AlBook. It does the same thing. Both of these PowerBooks have working batteries, but were also plugged into power at the time. I eventually plugged the display directly into that PowerBook, and it worked as normally. I fixed my display brightness and put it back into the KVM. What I can't figure out is why this would cause these PowerBooks to just shut off. There isn't anything special about the DVI cables used on the KVM and it uses just a standard single-link connection just like the 23" display does. The KVM works fine on every other devices I've plugged into it.