Abstract: A fiber optic control system with an electrically isolated control module that regulates the operation of a first and a second electrically operated device. A control module receives light on a fiber optic input cable from a control light source. An adjustable control in the control module provides a light of adjustable intensity from the control light source to a first and a second fiber optic output cable. The intensity of the light to the fiber optic output cables is adjusted by moving a reflective surface to vary the length of the light path. The reflective surface can also be rotated to terminate the light reflected to the fiber optic output cables. The first fiber optic output cable is adapted to convey light from the control module to a signal converter which controls the first electrically operated device in accordance with intensity of the light conveyed by the first fiber optic output cable to the signal converter.