US Patent 7525992 Automatic communication channel fault mitigation

A physical layer device having a corresponding method comprises a coding circuit to transmit first data, and to receive second data, at one of a plurality of data rates; and a communication circuit to transmit first signals representing the first data, and to receive second signals representing the second data, over one or more of a plurality of channels; a test circuit to determine a condition of the channels; and a control circuit to select the one of the plurality of the data rates, and to select the one or more of the plurality of the channels, based on the condition of the channels determined by the test circuit.