| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic fire alarm system that makes it possible to save more on wiring.SOLUTION: An automatic fire alarm system 10 comprises a receiver 2, a first detector 11 for transmitting a fire signal, and a second detector 12 for transmitting an interlock signal or a fire signal. The receiver 2 has a voltage application unit 2a for applying a voltage between one pair of electric wires 10a, and a receiving unit 2c for receiving a fire signal and an interlock signal. The second detector 12 is provided with a transmission unit 1a for making the one pair of electric wires 10a shorted and transmitting a fire signal and an interlock signal between the one pair of electric wires 10a using current signals each of which differs in current value, and a control unit 1b for controlling the transmission unit 1a. The second detector 12 and the receiver 2 are configured in such a way that the fire signal and the interlock signal are distinguishable by the current signals flowing in the one pair of electric wires 10a.SELECTED DRAWING: Figure 1 |
