| 摘要 |
PURPOSE:To detect a faulty communication system without cutting off the communication system, by providing a means to add a check signal to the data given from the own end office. CONSTITUTION:The data A1 given from a data generating part 16 of an end office 1 is sent to end offices 2 and 3 from a transmitting part 11 via an OR circuit 15. At the same time, receiving parts 12 and 13 receive data (B1, b2 and b3) and (c1, c2 and C3) from the end offices 2 and 3 and checks the received data through a discriminating circuit 14. Then check signals a2 and a3 showing the result of check are added to the data A1 to be sent to the offices 2 and 3. Thereafter the same check is given also to the offices 2 and 3. When the result of discrimination of the office 1 is confirmed by the received data B1 and the check signal c2, the transmission system of a route R2 is decided to normal. While the route R2 is decided faulty if no confirmation is obtained for the B1 and c2 although the c1 and b3 are confirmed. |
