Nohmi Bosai Ltd.

Yukihiko Usami

Kaoru Takahashi

Keiichi Takahashi

Kouichi Hishino

An object of the present invention is to provide a fire alarm system which is adaptable to form a large-size fire alarm system and is capable of causing a receiving portion to quickly detect fire information from a terminal unit, or the like, if the terminal unit has been operated. In a fire alarm system in which terminal units, such as fire detectors, are connected to the receiving portion, an address is given to the terminal unit to allow detection of terminal units that have a status change, wherein system polling or the like for a specific terminal unit, such as a transmitter, among the terminal units is performed prior to performing system polling of other terminal units.

Fire alarm system

A transmitter for use with a fire alarm system controls the monitoring of devices to be controlled based on a control command transmitted from a receiving section such as a fire receiver. With this transmitter, even if there is a short circuit in control lines for connecting the transmitter and the devices, it is not necessary to exchange fuses, and it is also possible to avoid the waste of power consumption which would otherwise incur during the actuation operation of the device(s). When the short circuit is recovered, the transmitter is able to correctly actuate the device(s). A small reverse current is permitted to flow in the control lines so as to enable the monitoring of a short circuit in the control lines by the transmitter. When the transmitter receives an actuation command from the receiving section, and if a short circuit in the control lines is detected, the transmitter goes into a standby state in which it holds an actuation signal for actuating the device(s) from being output to an actuating section. When the short circuit is recovered, the transmitter outputs the actuation signal to the actuating section.

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Tokyo, Japan

Yukihiko Usami