Abstract: The present invention provides a high-speed decoder for decoding signals encoded into Nordstrom-Robinson 16,256,6 non-linear code. The novel decoder receives a transmitted encoded signal in the form of a multi-dimensional vector to be decoded. The decoder comprises a plurality of computing elements coupled to the input encoded signals and produces modified multi-dimensional vectors and subcode values which are decoded in a plurality of subcode decoders to produce intermediate inner product values and information words associated with the intermediate inner product values. The intermediate inner product values are compared in comparator means to provide the maximum intermediate inner product value and its associated information which is indicative of the best mathematical estimate of the encoded signal being decoded.