| 摘要 |
PURPOSE:To attain sure route changeover by supervising transmission voice information of common use and space routes and controlling the route changeover based on the result of supervision. CONSTITUTION:When transmission voice information from a terminal transmission section 1 is inputted to a transmission input terminal SIN of a branch circuit 10, the circuit 10 branches the information and outputs it to the common use route via a transmission output terminal SOUT1 and to the spare route via another transmission output terminal SOUT2. The output information and a synchronizing signal are received at a carrier receiving section 4 at an oppsite terminal via each carrier transmssion section 3 and a transmission line 5 of the common use and spare routes and inputted respectively to a receiving switching circuit 20 and a receiving signal selecting circuit 22 via receiving input terminals RIN1 and PIN2. The circuit 22 supervises always said input signal respectively to discriminate propriety of the common use and spare routes and transmits route switching information to a receiving switching control circuit 21 when the information is obtained, and the circuit 21 makes the circuit 20 perform the route switching operation. |
