What's wrong with traditional classes of KVM switches ?

Ranking problem #1:  Video resolutions changed or Icons on desktop re-located while changing between/among connected Windows 7 or Windows 8 systems of KVM switches. Caused: The KVM switches does not pass correct EDID of the display/monitor to systems connected to the KVM switches.    Solution # 1 . Adding an EDID emulator in between each connected systems and kvm switches                     Solutions #2 .  Upgrade or replace your KVM switch with Video DDM KVM  or "DDM class" KVM switches .  The Video DDM= Full-time All DDC-EDIC function which provide dynamic EDID feeding to each connected systems of KVM switch. Ranking problem #2 :  My Logitech wireless Unifying Receiver devices (keyboard/mouse) can not work with my KVM switches.   Caused: the "Device Stage" of the Windows 7/8 requested to check the status of all connected I/O devices (including monitor, keyboard, mouse or tou...

With the popularity of USB; USB keyboards, mice and I/O devices are still the most common devices connected to a KVM switch. The classes of KVM switches reviewed are based on different types of core technologies in terms of the KVM switch handling USB I/O devices--including keyboard, mouse, touch screen display, etc. (USB HID class devices- Human Interface Devices ). 1. USB HUB based KVM Also called Enumerated USB KVM switch . A connected/shared USB device is required for the full initiation process (USB enumeration) EVERY TIME the KVM is switched to another target system/port. The switching to different ports is just as if you were to physically plug and unplug a USB device into your targeted system. 2. Emulated USB KVM Dedicated USB console port(s) are assigned to emulate special sets of USB keyboard or mouse switching control information to each connected/targeted system. Emulated USB provides an instantaneous and reliable switching action that makes keyboard hot...

If your KVM switch does not allow you to switch ports/channels by hitting the hot-key combinations, then you have a "HUB class" KVM switch. For the "Emulated KVM Switch class,” you’ll find that there is a specifically assigned USB port that you can plug your keyboard into for the hot-key commands. For both "Semi-DDM class" and "DDM class" KVM switches, there is no difference in which DDM port you can plug your keyboard into for the hot-key commands. As long as you plug in the keyboard or the wireless USB dongle to one of the DDM ports (normally there are at least two DDM ports/ KVM switch) you will have hot-key commands. Most importantly, you could have up to two connected keyboards (one for each DDM port) and the hot-key commands would work on both keyboards between all of the connected systems. The difference between "Semi-DDM" and "DDM" KVM switches are: 1. Semi-DDM switches still cause delays (but very short) when swit...

It's happened when you the "emulated class of KVM switches". In short, no matter what kind of keyboards or mouses you plug in the KVM switches, emulated KVM switches will only "emulated" "assumed" that your keyboards or mouses are the "simple and standard" keyboard and mouse. That's the reasons why your Logitech Unifying Receiver and Microsoft Wireless Receiver not work or work but just act as standard keyboard and mouse.   There are impossible for an emulator cover all kind or USB HID devices,.  So when you using this kind of KVM switches, the manufacturers will tell you that you must put your keyboard and mouse on the assigned USB ports accordingly.   Keyboards must plug in to the keyboard port of the KVM and mouses must plug in to the mouse port of the KVM.  If you don't do so, you can not use special hot-key commands or special mouse click commands to control the KVM switches. What a big deal for not using special keyboards ...