Systems and apparatus for providing supplemental functionality to a computer system with an expansion card adaptable for both internal and external coupling to the computer system. An expansion card has a bracket for internally coupling to a host computer and a housing for external coupling to a host computer. The expansion card may receive power from the host computer via an edge connector when internally coupled and through a power adapter via a power port when externally coupled. The expansion card may further receive data from the host computer via the edge connector when internally coupled and through an external bus when externally coupled. When externally coupled, the expansion card is mounted within a housing that may be mounted to an outside surface of a computer rack to preserve space within the rack.