KVM problems with Windows 7 and Windows 8

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 touch-screen if equipped... etc..),  If you're using "Hub-based class" KVM switch, the re-enumeration process will be trigger "every time" when you make a selection or switch to different connected systems to the KVM switch.  The re-enumeration of USB hub will caused devices HPE (Hot Plug Error) and long-delay caused by the re-enumeration procedures -which will cause unstable operations of connected systems.        If you're using "Emulated class" KVM switch, you may not experience USB re-enumeration when you switching to different ports,  However,  the Unifying Receiver for the emulated KVM will be treaded as "standard" keyboard and "standard " mouse,  you simply can not control or even pairing the Unifying Receiver under Logitech's device control software - SetPoints (for Windows) or Logitech Control Center (in Mac OS).  

  • Solution: Upgrade or Change to DDM class KVM switches.   The DDM switches will provide transparent USB HID to all connected systems of DDM KVM switches.  So, you will see what you connected to the KVM as the same as what you connected directly to the systems.   At the same time, DDM technology will maintain the communication "as the connected devices" are never left, even when the devices switching away to different ports/channels. 

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