This housing can accept a total of six modular KVM extender cards for the DKM and has a power redundancy option. Four housings are available desktop housing for two four or six boards or a 19-inch 4U rack for 21 boards. A redundant power supply option is available in some housings. The 6-port chassis has an internal AC/DC power supply and an external power supply option. Can be rackmounted with ACXMODH-RMK. The DKM HD Video and Peripheral Matrix Switch System is comprised of a modular housing chassis with 2 4 6 or 21 slots and transmitter and receiver interface cards. The DKM extender setup provides the widest range of possible combinations which makes it easy to customize for your specific application. These DKM components are part of a modular system. You will need to contact Black Box to have them assembled to fit your application. To configure your DKM setup call our FREE Tech Support.