A distribution network power line communication system divided into addressable communication zones defined by signal repeaters located at spaced intervals along the distribution network. The signal repeaters are switchably disposed in signal communication between the primary and grounded neutral conductors of the primary distribution network. Each repeater, when uniquely addressed by an interrogation signal from a central communication terminal, transfers the interrogation signal from the primary conductor to the primary grounded neutral conductor whereon it is transmitted to a uniquely addressed remote communication terminal coupled to a secondary neutral conductor within the communication zone of the signal repeater. A timely response signal from the remote communication terminal on the grounded neutral conductor is transferred by the repeater to the primary conductor and then to the central communication terminal. Coupling circuitry, responsive to repeater logic section control signals, connects the receiver and transmitter sections of each signal repeater to either the primary or grounded neutral conductors of the distribution network for signal amplification and bidirectional signal transmission.