A fire alarm system includes a transceiver. The transceiver has: a housing; conductors for receiving power from power lines; power output conductors for transmitting the power to a local alarm; and a connector for the alarm conductor of the local alarm. The transceiver has a trigger circuit, responsive to an alarm condition. A transmitter circuit responds to the alarm condition by injecting a signal onto a power conductor, using power line carrier technology. A receiver circuit responds to a second signal, similar to the first signal, by triggering the transmitter circuit; and by triggering the local alarm.