| 摘要 |
PURPOSE:To obtain a terminal line adaptor diagnosing individually the circuit operation of each device by providing a selection connection circuit demarcating in detail line circuits and combining them optionally and a trunk circuit inputting/outputting a pseudo transmission signal. CONSTITUTION:The selection connection circuit 80 applies a prescribed connection according to a command inputted from a common bus line 9 and holds the state till the end of the diagnosis. For example, in connecting a transmission data signal from a transmission circuit section 2,012 of a line circuit 201 to a reception circuit section 2,013 as shown in the arrow A, a return loop of the own terminal line is constituted. In connecting a transmission data signal from the circuit section 2,012 to a reception circuit section 2,023 of a line circuit 202 as shown in the arrow B, the return loop bridged over the lines is constituted. In connecting a transmission circuit section 402 of a trunk circuit 40 and a circuit section 2,013 of the circuit 201 as shown in the arrow C, the transmission test circuit of a pseudo transmission signal to a terminal line is constituted. The diagnosing operation as above is executed continuously to generate a program and it is executed, then a fault is prevented in advance.
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