Abstract: The power line communication system includes a transmitter and a receiver, both providing a communication path between two communication control devices over a power line. The transmitter includes a voltage amplifier and a current amplifier. A switch between the transmit and receive modes is implemented within the voltage amplifier. The current amplifier also has a two-step output impedance. When the transmitter is active, the current amplifier shows a low impedance on the line to overcome other loads. If, however, the communication medium shows a high level of noise, the output impedance of the current amplifier decreases even further and creates a path to ground. The receiver advantageously uses a logarithmic amplifier for signal range compression. This type of amplifier preserves the shape of the signal that is important when the modulation scheme uses the zero crossings to store information.