The Master Command Unit, which can also be referenced as a master-control unit, was a compact, box-shaped device equipped with various switches, typically attached to a belt. This device managed several smaller applications, including illumination, gateways, and communications. Furthermore, the unit was capable of interfacing with more complex systems, such as the main defense and safety protocols. However, the master-control unit was not autonomous and required supplementary hardware to establish a connection between the small unit and its main control circuits. Prior to its obliteration circa 2 BBY, the auxiliary system located at Stars' End incorporated receptor circuits embedded within the tower's walls, consistently located near the master-control unit carried by Viceprex Hirken.