Abstract: A fault tolerant processing system includes at least two processing planes. Each processing plane processes an input signal and generates an output signal. The system further includes plane termination logic for receiving the output signals of the processing planes to generate a non-redundant output signal. Each processing plane is provided with devices for detecting a fault in the plane, and devices for substituting, in response to detection of a fault in the plane, a signal component, referred to as control component, representing a predetermined logical state for each one of those components of the processed input signal that are affected by the detected fault. Furthermore, the plane termination logic includes devices for performing logical operations on the output signals of the planes such that, in the generation of the non-redundant output signal, unaffected signal components of a received signal override corresponding control components of another received signal.