Duplex communications are facilitated. In connection with various example embodiments, current sources are used to drive transistor-based circuits coupled across a first resistive circuit, to send signals on a communications medium. While driving the transistor-based circuits, the current sources are used to drive reference transistor-based circuits coupled across a second resistive circuit. A differential output signal based upon a power-related value across the first resistive circuit, less a power-related value across the second resistive circuit. This differential output signal characterizes a power-related value corresponding to a received signal on the communications medium, as gleaned from a total signal corresponding to both transmitted and received signals, less a signal corresponding to the transmitted signal.