Abstract: A ringing suppression circuit is provided at one or more nodes each having a communication circuit executing communication with another node by transmitting a differential signal through a pair of communication lines connected to the nodes. The circuit includes a suppression circuit and an operation mode controller: The suppression circuit is configured to execute a suppression operation for suppressing ringing in the differential signal. The operation mode controller is configured to set an operation mode of the suppression circuit to one of: a normal operation mode, which enables the suppression circuit to execute the suppression operation in response to detecting a change in a level of the differential signal, and a permanent off mode, which disables the suppression circuit to execute the suppression operation on a steady basis.