COMMUNICATION SYSTEM AND COMMUNICATION DEVICE

PROBLEM TO BE SOLVED: To provide a communication system capable of reducing the possibility that the controller deals as usual with data that has been incorrect by interference although permitting interference in a communication device in which two communication devices communicate with a controller shared with each other using the same communication line.SOLUTION: A TPMS receiver 3 starts sending a signal based on a plurality of data bits included in one frame to up signal lines 9a and 9c when sending the one frame to a body ECU 5 and compares a signal sent to the up signal lines 9a and 9c with an FB signal input from a self-check wire 9e during sending the signal. As a result of the comparison, when both mismatch, a predetermined invalidation signal (low level signal) for compulsorily setting the signal level of the up signal lines 9a and 9c at a predetermined signal level only for a predetermined invalidation period is sent to the up signal lines 9a and 9c to make the body ECU 5 lose the one frame.