| 摘要 |
PURPOSE:To discriminate the cause of failure, by providing a means requesting failure cause discrimination informtion for a communication device, when the reception timeout of a fill-in signal takes place in a CPU. CONSTITUTION:The CPU1 transmits an instruction signal of a cause of failure discriminating information request to the communication device 2 of a station itself via an information transmission line 4. The device 2 receiving the signal transmits the discrimination information of causes to failures set in a failure detection storage means to the CPU1, where the discrimination information is interpreted to discriminte in which part among the device 2, a remote station 9 and a communication line 7 the failure lines. If a failure which can not respond to the failure cause discrimination information request from the CPU1 takes place in the device 2, the CPU1 discriminates the presence of the device 2 through the absence of the response from the device 2. |
