A communication system includes a first beacon arranged in association with an installation position of a first machine that performs communication in a first frequency band containing a frequency of at least one advertising channel. The first beacon is configured to transmit a first beacon signal at a first advertising channel that falls outside the first frequency band. The communication system further includes a mobile communication device configured to perform a first communication at an advertising channel that falls outside the first frequency band upon satisfying a predetermined condition in a state of receiving the first beacon signal and that differs from the first advertising channel.