DATA COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To prevent the interference of data transmitting and receiving when a plurality of persons who carry data communication devices exist in the nearest distance, in the data communication system in which data transmitting and receiving between the data communication devices 10A, 10B which are worn on a human body and a data communication device 20 through a human body. SOLUTION: The 1st data communication devices 10A, 10B receive start signals from the 2nd data communication device 20 (S101), the 1st data communication device 10B whose delay time is short transmits a start notice signal. The 1st data communication device 10A whose delay time is long determines that signal transmission and receiving is carried out between the other 1st data communication device 10B and the 2nd data communication device 20 if it receives the start notice signal (YES in S102), and outputs an interference notice signal (S106). The 1st data communication device 10A, the other 1st data communication device 10B and the 2nd data communication device 20 which receive the interference notice signal in S104, S203 perform predetermined error processings (S107, S108 and S205). COPYRIGHT: (C)2006,JPO&NCIPI