Expansion card for TX units add Audio, USB 2.0(36Mbps) and RS232 Works over CATx cabling, and multimode or single-mode fiber cabling. Supports RS232, analog audio, and USB 2.0 devices. Requires connection to main board. Part of the DKM HD Video and Peripheral Matrix Switching System is comprised of 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 new 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 HD Video and Peripheral Matrix setup, call our FREE Tech Support.