| 摘要 |
PROBLEM TO BE SOLVED: To provide an alarm transmitter capable of receiving the sensor information of a sensor that is connected behind a disconnection place even if a part of a communication line is disconnected and to provide an alarm transmitting method. SOLUTION: This transmitter normally requests sensor units S1 to Sn for sensor information according to forward polling from a sensor information receiving part 2 through sensor information line 117, monitors responses from the sensor units S1 to Sn, detects it as disconnection if a response does not come for a fixed time, further requests the sensor units S1 to Sn for sensor information according to backward polling and obtains disconnection position information and operable sensor unit information. While the sensor information line 117 is disconnected, forward and backward polling communication is further performed to the sensor units S1 to Sn and disconnection restoration information is obtained.
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