So for example; We have one large monitor that has 4x HDMI ports on the back. We can then plug 4x different computers into the monitor. Your keyboard and mouse plug into the KVM switch.
Theoretically, it should support HDMI 1.3a ... four USB host ports (to connect a mouse, keyboard, and anything else), and a connector that goes to the keypad. The keypad has a 3x3 grid of buttons.