Hochiki Corporation

Takehiro Ono

Akira Ishida

Shigeru Kaneko

Yoshihiro Matsuda

A fire detector is connected to a loop transmission line connected to a receiver. When the loop transmission line is normal, a transmission unit is connected to the fire detector. When a disconnection failure occurs, a disconnection monitoring unit turns on switching circuits to connect the end of the loop transmission line to the transmission unit, and the receiver connects to the fire detector from both ends of the loop transmission line. An input/output switching booster is inserted and connected in the middle of the loop transmission line, and when the start side transmission line is disconnected and the switching circuits are turned on, the input/output is switched. Accordingly, the input/output switching booster amplifies the down signal input from the terminal side transmission line and outputs it to the start side transmission line and at the same time amplifies the up signal input from the start side transmission line.

Fire alarm system and booster

A fire detector is connected to a loop transmission path connected to a receiver. When the loop transmission path is normal, a communication connection is made from a transmitting unit to the fire detector to monitor fire. When a break fault occurs in the loop transmission path, a break monitoring control unit turns switching circuit units ON to connect a termination of the loop transmission path to the transmitting unit. To the loop transmission path, a relay detects a current normal direction at normal and a current reverse direction at the time of occurrence of a break for transmission to the receiver. When a break occurs in the loop transmission path, a break section determining unit of the receiver determines, as a break section, a section in which the current normal direction detected by a plurality of the relays is changed to the current reverse direction.

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Tokyo, Japan

Takehiro Ono