Patent ID: 7940860

Claim:
A communication system for communicating data, comprising: a transmitting device including a coder for encoding data of a primary signal to generate encoded data such that polarity of the encoded data alternates between positive and negative polarities, a polarity-reversed data generator for reversing the polarity of part of the encoded data to generate polarity-reversed data, and a transmitter for transmitting, as communication data, the encoded data including the polarity-reversed data; and a receiving device including a receiver for receiving the communication data, a polarity-reversed data detector for determining whether or not polarity of the received communication data alternates between positive and negative polarities, and detecting, as the polarity-reversed data, data of which the polarity differs from an expected polarity, and a polarity recognizer for recognizing the polarity of the polarity-reversed data and treating the recognized polarity as control information.