IHSE USA 474 Series Draco major - Manual (Page 37)

Safety Instructions
2011-10-11 37
If you have a Single-Head KVM/USB 2.0 console, you can also get access
to a Triple-Head KVM/USB 2.0 CPU. However, if you have a Single-Head
CPU, the second monitor will remain black and if you have a Quad-Head
CPU, control will only be given at monitor one and two.
However, control will only be given at monitor one. You cannot use the
USB periphery if you try to get access to CPUs without USB 2.0
connection.