Abstract: A counter value of a divider counter 3 that determines a communication speed is compared by a comparator 4 with a value calculated from a difference between fall delay and rise delay, and data is received with a matching signal serving as a data reception shift clock (S201), thereby acquiring receive data on the optimum position. Further, with the data reception shift clock (S201) serving as a data transmission shift clock (S201), the transmission control circuit 5 transmits serial data (S203) from the data transmission shift register 7 as data with a duty ratio reversed from a varied duty ratio of the communication system. Thus, it is possible to transmit data with a normal duty ratio to another communication device.

Abstract: A counter value of a divider counter 3 that determines a communication speed is compared by a comparator 4 with a value calculated from a difference between fall delay and rise delay, and data is received with a matching signal serving as a data reception shift clock (S201), thereby acquiring receive data on the optimum position. Further, with the data reception shift clock (S201) serving as a data transmission shift clock (S201), the transmission control circuit 5 transmits serial data (S203) from the data transmission shift register 7 as data with a duty ratio reversed from a varied duty ratio of the communication system. Thus, it is possible to transmit data with a normal duty ratio to another communication device.