An Ethernet interface selectively operates according to i) an asymmetric first mode in which transmission in a first direction and reception in a second direction occur at different data rates, and ii) a symmetric second mode in which transmission in the first direction and reception in the second direction occur at a same data rate. The Ethernet interface encodes a first bit stream to generate a first output data stream for transmission at the first data rate, and/or encodes the first bit stream to generate a second output data stream for transmission at a second data rate that is different than the first data rate. The Ethernet interface i) generates a transmit signal using the first output data stream when operating in the symmetric first mode, and ii) generates the transmit signal using the second output data stream when operating in the asymmetric second mode.