| 摘要 |
PURPOSE:To provide a warning system which is proof against interruption by a spectral diffusion communication system. CONSTITUTION:When mobile stations 304 and 305 receive polling from a fixed station 301, they return data showing that there is no abnormality. When there is abnormality, the content of abnormality is transmitted to the fixed station 301. When polling from the fixed station 301 cannot be received for prescribed time, an abnormal signal is continuously transmitted. On the other hand, the fixed stations 301-303 transmit data on the state of the mobile which the fixed stations 301-303 manage in accordance with polling from a control station 306 when there is no abnormality in the mobile station. When the abnormal signal from the mobile stations is received and a response signal for polling to the shift station is not received, the abnormal content is transmitted to the control station 306. The control station 306 issues a warning when there is abnormality in data from the fixed stations 301-303 and controls all the fixed stations so that the signal of the mobile station with abnormality is received. |
