In older control rooms, discrete control input devices (that is, devices that depend upon mechanical motion) are still the most common means for the operator to interact with the plant’s systems. These devices are limited to relatively primitive devices like buttons, switches and levers. As I&C and HSI technology evolves it is becoming possible to control plant components by means of direct manipulation devices like a computer mouse, joystick, keyboard or trackball. As computing power continues to increase, we can expect to see even more sophisticated devices finding their way into the control room and other work areas. In the not too distant future we can expect to see fixed as well as mobile devices that allow not only direct interaction through touch and force feedback, but also indirect interaction through gesture, speech and gaze.