| 摘要 |
A plurality of fire detectors for detecting a physical change caused by fire and a central signal station for receiving a fire signal from the fire detectors to raise an alarm are connected to each other through optical fiber cables. The central signal station transmits power light for supplying power and timing signals which are superposed on the power light for controlling operation timing to the respective detectors through the optical fiber cables, while each of the fire detectors converts the power light into electric power, carries out a fire detecting operation in response to the timing signals and transmits, upon detection of a fire, a fire signal in the form of light to the central signal station through the optical fiber cable. |
