A digit signal processing system may include a near end and a far end connected by a pair of signal transmission paths. A signal processing may be located at the near end through which signal commands are transmitted to the far end. A signal transducing device may be located at the far end to receive the signal commands and to transmit to the near end signals indicating the state of the signal transducing device. A signal canceller may be operatively associated with the signal processor to subtract undesired signals from the received signals. The signal canceller may employ Auxiliary-Vector filtering.