| 摘要 |
PURPOSE:To increase the reliability of selection system, by ensuring the discovery of failures in the transmission system and transmission control station of major system and transferring the transmission control to the transmission system and transmission control station of the waiting system. CONSTITUTION:Double transmission lines 17,18 are used for the information transmission between a plurality of transmission and reception stations 16, and the transmission lines 17,18 are provided with the transmission control stations 14,15 managing the transmission. In such a transmission system, the stations 16,14 and 15 of the transmission system are provided respectively with the monitor separation circuit 20 to operate the relay 26 performing self diagnosis, and when the result of self diagnosis is in failure, the station itself is separated and when normal, reapplication is made. Further, the number reapplied every station is counted with the counter 24, and when the counted number is more than a given value, the transmission lines 17 and 18 are selected by the relay 27 to select the station 14 of the major station to the station 15 of the waiting system. Further, in the station 16, the transmission line of the major system is selected to the transmission line 18 of the waiting system. |
