SC420 KVM Switch allow desktop IT administrators to deploy a single CAC reader that will switch to all computers connected to the switch. (CAC support is required for all government employees attempting to log in to government systems and is specified in the Homeland Security Presidential Directive 12 [HSPD12].) Both switches include three layers of tamper-proof hardware security at the desktop. In addition, SwitchView SC420 switche ensure that only USB human interface devices (HID's) function on target computers by constantly monitoring all devices attached to the console ports. These switches ignore communication from non-HID's (such as flash drives, hard disk drives, cameras and printers) when switching data to the target.