a system for locating an impairment in a coaxial cable network comprises an encoder , an impairment detector , and a decoder . the encoder couples to the network at a predetermined encoding point , upstream of the impairment . the encoder automatically encodes an identification code on a signal originating downstream of the encoding point and associated with the impairment . the impairment detector couples to the network at an access point , upstream from the encoding point , and receives signals from the network . the detector is adapted to detect from the received signals the signal associated with the impairment and generate a detected version of the signal . the decoder is adapted to decode the identification code from the detected version of the impairment signal . once the identification code is determined , the encoder and encoding point are identified , and the location of the impairment is determine to be downstream of the encoding point .