FIRE ALARMING DEVICE

PURPOSE:To enable polling transmission between a receiver and a terminal without requiring any address by utilizing a spectrum spread communication. CONSTITUTION:Each of repeaters 14-1 to 14-n is provided with a pseudo-random series generation part 20 which generate a different and characteristic pseudo- random series previously assigned to the corresponding repeater, a reception part 22 which receives and demodulates a signal from the receiver 10 by using the pseudo-random series generated by the pseudo-random generation part 20, and a transmission part 24 which sends the signal from the repeater to the receiver 10 by using the pseudo-random series generated by the pseudo-random series. Further, the receiver 10 is provided with a pseudo-random series switching generation part 30 which generates one of the same plural pseudo-random series as the characteristic pseudo-random series set in the repeater by switching, a transmission part 34 which sends the signal from the receiver to the repeater side by using the pseudo-random series generated by the switching, and a reception part 36 which receives and demodulates the signal from the repeater by using the pseudo-random series generated by the switching.