| 摘要 |
PROBLEM TO BE SOLVED: To provide a radio communications system with which the success rate of communication in a radio zone is improved and alarm moving to a center is prevented. SOLUTION: Any abnormality such as gas leakage occurs and a detector 8 transmits an alarm signal to a wireless hand set 7 (step 40). For example, as the first retry (1-(1)} of first transmission, the wireless hand set 7 transmits the alarm signal containing transmission time information and transmission time number information or the like to a wireless base unit 6. When the wireless base unit 6 cannot receive the signal for the 1-(1)st time because of any factor (step 41), after the lapse of one minute, the wireless hand set 7 performs 1-(2)nd transmission and the wireless base unit 6 normally receives the signal (step 42). The wireless base unit 6 analyzes the transmission time information and transmission time number information of the received signal and transmits the alarm signal to the center 2 (step 43). When the wireless hand set 7 performs 1-(3)rd transmission and the wireless base unit 6 normally receives the signal (step 44), the wireless base unit 6 analyzes the transmission time information and transmission time number information of the received signal and does not transmit the alarm signal to the center 2 when it is already transmitted to the center 2.
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