ATEN CS84U 4-Port PS/2-USB KVM VGA Switch - Control up to 4 VGA Computers for Windows, Linux, Mac, and Sun

If you're buying this for PS/2 support, honestly you need to look elsewhere.A rundown of some of the issues I've experienced (and yes, I even went through lengthy and unnecessary firmware upgrade for this unit which resolved a total of 0 of the following issues):USB Keyboard -> PS/2 Keyboard input: After about 10 seconds, I get stuck keys that won't un-stick unless I press them again. Games are unplayable using this combination.PS/2 Keyboard -> PS/2 Keyboard input: You'd think, wouldn't you. However = 0-key rollover. I'm dead serious. Any key presses immediately cancel the preceding keys held. Again, games unplayable.USB Mouse -> PS/2 Mouse: Overloaded PS/2 input. The DPI rating of literally any modern PS/2 mouse apparently is far too much for the PS/2 bus. PS/2 sends interrupt commands to the CPU which ask to be processed, so the DPI ratings of modern mice will very quickly overload any PS/2 system receiving them, unless the data is intelligently metered out to the PS/2 ports. Which, of course, it isn't using this device. The result is it actually can lock up the system until the mouse movement is processed, which yet again, makes even the most basic games unplayable. I have even had it cause stuck keys on physically attached keyboards.I had a support ticket out with the manufacturer which I've abandoned since it's been ignored for about a week. Chatting with another user of this same switch, I found that they told them "this unit is functioning as designed". So that's good.I 100% would avoid Aten products unless you're only using them to switch USB devices, and even then I would recommend against them for any gaming functionality unless explicitly stated in the manual that the devices support n-key rollover and have mouse DPI support ranges. Avoid for PS/2.