Communication systems adaptable to power line communications

A communication system and method of operating the same that includes, in one embodiment, a transmit filter including a transmit filter capacitor, and a receive filter coupled to the transmit filter. The communication system also includes a switch, coupled to an auxiliary winding of a transformer and to the transmit filter capacitor, configured to alter an impedance of the transmit filter during a receive mode of operation of the communication system. In another embodiment, a transmitter is configured to receive an input data stream, and produce a control signal for a switch-mode power amplifier employing a predetermined data sequence selected by the input data stream thereto.