A four-state joint brake module is provided to selectably stop or allow motion in both directions resulting in a mechanism that has four possible states: 1) allowing rotation only in a clockwise direction, 2) allowing rotation only in a counter-clockwise direction, 3) allowing free rotation in both directions, and 4) stopping motion in both directions. In robotic and other motion control applications the use of this four-state joint brake module in a multi-segmented linkage allows for position holding without continuous application of power and “fail safe” behavior. It further allows for the ability to toggle this useful state behavior independently in either direction and is relevant for robotic applications.