| 摘要 |
PURPOSE:To inform a failure in an office via a PCM carrier, by connecting a signal line of the PCM carrier to a digital exchange via a digital trunk and directly accommodating the PCM carrier to the digital exchange as the digital signal. CONSTITUTION:An output of an interface circuit 17 is introduced to a digital tone inserting circuit 18. The output of the circuit 18 is given to an exchange 10 via an incoming highway 19. The output of the exchange 10 is given to a digital tone inserting circuit 21 through an outgoing highway 20. The output of the circuit 21 is given to the circuit 17 and a signal line 3 is given to the circuit 17. The output of a digital tone generating circuit 22 is given to the circuits 18 and 21. A wind signal of a control circuit 23 is given to the circuits 18 and 21. The other output of the circuit 23 is given to the circuit 17 and the other outputs are given to the exchange 18. A failure monitor circuit 9 is connected to the circuit 23. Thus, the digital trunk 15 is provided and the PCM carrier is given to the exchange 10 via the trunk 15. |
