| 摘要 |
PROBLEM TO BE SOLVED: To provide a fire alarm facility where a fire can be detected within necessary time even if the error of a clock pulse frequency in a type of the facility that oscillates a clock pulse only by resistance, a type of the facility that oscillates the clock pulse only by resistance and a capacitor or a type of the facility that oscillates the clock pulse by a microcomputer incorporating them becomes±200%. SOLUTION: In signal transmission, a fire sensor corresponding to a polling output signal from a fire receiver returns a response output signal. In the fire alarm system, the fire receiver transmits two reference pulses having the duration of prescribed reference in the polling output signal. The wire sensor receives the two reference pulses and takes the timing of the response output signal in accordance with the duration of received two reference pulses.
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