When is a KVM switch not a KVM switch?

 

Around 8 years ago, I bought a KVM switch to use in my business in order to control 2 PC's at a time - 3 years later, I needed something bigger, I needed to control 4 PC's instead, so I bought a 4 Port PS2 KVM switch, I tried that for a period, but because it was a manual type, I had to press a button before it would cycle through the connected PC's and also, keyboard and mouse support was very flaky (sometimes it work on one PC & sometimes it doesn't on any)..

Because of those niggles, I decided to go back to the original KVM switch until I can get another, and soon afterwards I did - This time a 4 port USB KVM switch (like the picture) - This was also a manual one, so I decide to keep it on one side until needed...

Few weeks back, my original KVM switch decided to "kick the bucket", so I had no option but to use either the PS2 or the USB effort.. I started with the PS2 one and after a few days, this really drove me potty, the mouse and keyboard didn't work on any of the PC's which defeats the object of having a KVM switch, however the display did work, but I still needed a mouse and keyboard set per PC, so and in desperation, I decided to use the "NEW" USB KVM switch, and exactly the same as the PS2 one, you can see the image but you cannot control the mouse or keyboard on any PC...

So the answer is:

When it's a piece of Chinese crap that does not work...