Dell KVM 4161DS - Manual (Page 115)

Virtual Media 99
Reserving a Virtual Media Session
If you want to continue a virtual media session after the KVM session is
closed, you can reserve the virtual media session. If the virtual media session
is reserved, it will remain active when the associated KVM session is closed. In
addition, the virtual media session can only be accessed by the user to which
it is reserved.
To reserve a virtual media session:
Select the Reserve checkbox.
Resetting the USB Bus
The USB reset feature resets every USB device on the target device, including
the mouse and keyboard. It should only be used when the target device is not
responding.
To reset the USB bus:
Select USB Reset.