| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a communication validity determination system, capable of precisely determining whether or not it is illegal communication that uses a repeater.SOLUTION: A time zone is provided in which electric waves are transmitted at the same time from a terminal 2 and a communication unit 18, and collision is made to occur with these electric waves. The communication unit 18, during communication, receives the electric waves at a receiving part 22, without discriminating which of the terminal 2 or the communication unit 18 has transmitted the electric wave. Based on change in a detection voltage Vx that is detected with the receiving part 22, validity of communication is determined. A validity determination part 26, if a value when the collision is settled does not represent "0" or a value being lowered by a predetermined amount, at the detection voltage Vx that is detected by the receiving part 22, determines a communication being executed to be valid communication. If a value represents "0" or a value being lowered by a predetermined amount when the collision is settled, the communication being executed is determined to be invalid communication.</p> |
