RADIO CHANNEL MONITORING SYSTEM

PURPOSE: To realize a radio channel monitoring system which is capable of monitoring the radio channel up to an intermediate repeating part which does not become a line fault also when the radio channel in a monitoring section becomes the line fault and the main signals between terminal stations are not normal. CONSTITUTION: A terminal station 11 has a function multiplexing a mode information transmission request signal in the main signal to be transmitted to an intermediate repeating part 31, separating the state information multiplexed in the main signal from an intermediate repeating part 41 and holding the alarm state of a pertinent station performing the transmission request of the state information. The intermediate repeating part 3i has a function branching the transmission request of the multiplexed state information from the terminal station 1 1 and transmitting state information to the terminal station 11 via the intermediate repeating part 4i when the present station is pertinent to the transmission request of the state information from the terminal station 11. A terminal station 21 receives the main signal from the terminal station 11 for which the intermediate repeating is performed and transmits the main signal in the direction of the terminal station 11 via an intermediate repeating part 4n.