US Patent 7797592 Automatic communication channel fault mitigation

A physical layer device includes a coding circuit to transmit first data, and to receive second data, at one of a plurality of data rates. A communication circuit transmits first signals representing the first data, and receives second signals representing the second data, over one or more of a plurality of channels. A test circuit determines a condition of the channels. A control circuit selects the one of the plurality of the data rates, and selects the one or more of the plurality of the channels, based on the condition of the channels determined by the test circuit.