| 摘要 |
<p>PURPOSE:To prevent a system-down of a transmission system by forming the systems of transmission line loops to terminal stations from a central station in two pairs while utilizing transmission lines among the terminal stations in a unit. CONSTITUTION:When a disconnection is generated in a transmission line 16b in the system 16, the loop constituted by transmission lines 16a, 16b, 16c is cut and the function of the loop stops, but the loop constituted by transmission lines 15a, 15b, 15c of the system 15 is normal. Accordingly, the terminal station 3 and the terminal station 5 are each given control commands received from the central station 1 through the terminal stations 2 and 4. With monitor informations which must be transmitted over the central station 1 from the terminal station 3 and the terminal station 5, informations being transmitted to the terminal stations 2 and 4 are connected to reception messages at the terminal stations 2 and 4, and transmitted to the central station 1 through the transmission lines 15b, 15c.</p> |
