I have the item working. It was a hardship to lose my Belkin ps/2 but modern requirements and a problem with a monitor that had a button refusing to darken the display when needed in Linux meant a change to DP graphics cards and monitor.I powered this device up weeks ago but did not fully test it. 16K, 8K and 4K cables are fine as long as the plastic ends are not to large to fit into the PC. Replacement USB cables for the short but well made supplied cables MUST be 3.0.This KVM is connected via my new Dell 8K G2725D. The switches between 1 & 4 have a good click , little delay moving between the displays. Initially I changed from my Compaq server keyboard costing £100.00 2rd for a German designed Perixx Periboard-106 and a good price - looking similar to the now wonderful but unavailable IBM PS/2 and a reasonable feel and strength to the buttons.The KVM switch its self is well packaged , sturdy metal box , LED light for each PC its on. It is supplied with 4 USB cables and an IR cable plus warranty card.UPDATE: In fact this KVM will 16K cable but not of course at 16K - my issue there was a Centurion Cooler Master 2008 PC case that wont allow the particular 16K cable I had to fit properly but my other Cooler master 2010 does. One must use USB 3.0 replacement cables not 2.0. Next occasionally you may need to turn display off and back on if display not established. Next I would suggest labels for PCs on the KVM front and back top side to avoid confusion. The numbers from a forward view will read 1-4 at the front and 4-1 at the back so one constantly assumes like my old Belkin that button one at the from on the left relates to cables one on the left at the back - it doesn't.Next the USB slots are in fact for some reason a much better fit on the KVM than the USB 2.0 that I should not of been using anyway. On my Dell G2725D Monitor and Nvidia K2200 I am running at a recommended 2560 x 1440 on all 4 PCs. The remote works great.There is a slight issue of interference on one PC with all 4 units working but I hope to resolve that soon.I looked about and could not find a simple way to upgrade my monitor to a descent predicable default resolution with good reviews until I saw this KVM - then I purchased my monitor. There is an after sales card in the box offering a 2 year warranty with an email address. This system should be Ok in a small server room and the PS/2 keyboard will be fine with the new IC PS/2 TO USB adapters. No issues with the front USB ports - they work great with my USB 2 stuff and mice , keyboards.