Abstract: A fire receiver enables a fire alarm system to be reliably set up while the work for installing the fire alarm system is simplified, even if an IC card storing necessary data cannot be prepared or even at a time when the operation of connecting all terminal devices to the fire receiver is not completed. When a connection of the IC card to a card reader is detected when power supply to the fire receiver is turned on, data stored in the IC card is fetched and the terminal devices are operated on the basis of the fetched data. When no connection of the IC card to the card reader is detected when the power supply is turned on, predetermined data is fetched from the terminal devices by polling the terminal devices, and the terminal devices are operated by the data fetched by polling.

Abstract: A fire alarm system has address numbers that are given to terminal devices, such as transmitters, analog fire detectors and addressable fire detectors, and are given to the fire receiver similarly to the foregoing terminal devices. A signal to be transmitted from the fire receiver is given the address of the fire receiver as the sender address as well as the addresses of the terminal devices which are the information receivers, and a signal to be transmitted from the terminal device is given the address of the receiver of the signal as well as the self-address. As a result, information can be directly transmitted to the terminal devices, and therefore, the load of the fire receiver can be reduced. When the fire receiver and the terminal device transmit the data signal, a data length signal denoting the length of the data to be transmitted is calculated, and the data length signal is transmitted together with the data signal.

Abstract: In a fire alarm system one of a fire receiver and terminal devices transmits the same signals in opposite transmission directions to first and second loop-signal lines. The remaining ones of the fire receiver and terminal devices receive the signals transmitted through the first and second loop-signal lines and detect whether there is an abnormality in transmission by detecting differences in the receiving times of the signals. Consequently, an abnormality of transmission is detected immediately. A fire receiver or terminal device which detects any abnormality immediately causes the first and second loop-signal lines connected with each other to form a signal loop-back path, thereby transmitting signals to the entire loop-signal line except to the position where the abnormality occurs. As a result, the reliability of signal transmission is significantly improved.

Abstract: A power supply control device is provided in a fire alarm system having terminals such as fire detectors and/or repeaters with comparators to detect abnormalities such as fire or an operating status of controlled apparatus, and is equipped with a reference voltage supply a source to supply reference voltage to the comparators, and a power supply control to allow the reference voltage to be supplied to the comparators only during the detecting time.

Abstract: A line interruption supervisory device for a fire alarm system is capable of reliably carrying out the line supervision even if the line length is long and/or there is a large number of connected fire detectors. To this end, a terminating capacitor is connected across the terminal of a pair of power/signal lines to which fire detectors are connected. A memory first stores the voltage available on the power/signal lines when the line supervision is requested, immediately followed by the interruption by a cut-off circuit of the power supply to a pair of power/signal lines, and further followed by a comparison of the voltage available on the power/signal lines before the power supply interruption with a line voltage available after a lapse of a predetermined time from the power supply interruption by a line interruption discriminating circuit to determine, according to any difference between these voltages, whether there is an open power/signal line.

Abstract: A fire alarm system includes a receiver unit such as a fire control panel or a repeater having zone lines connected thereto, with various types of fire detectors being connected to the zone line. Supervising power is normally supplied to the zone lines. When the receiver unit receives a fire signal via a zone line from a fire detector, the receiver unit decides from what type of detector the fire signal was transmitted. Types of fire detectors include, for example, a type having as switching means only a mechanical contact for causing said zone line to be in a short-circuited condition, a type having as switching means a switching circuit with a self-holding function, or a type having a response lamp.