| 摘要 |
PURPOSE: A duplexing device of a full electronic telephone exchange is provided to increase a reliability of the full electronic telephone exchange by equipping a circuit device for duplexing inside the first board and the second board which are duplexed each other. CONSTITUTION: An NOR operation circuit(20) receives information about an activity state and a failure state of an opposite board, and performs an NOR logic operation. At this time, each of two input terminals of the NOR operation circuit(20) is connected to a full up resistor(R1,R2). An NOT circuit(22) inverts a restarting signal(/RST), and the first OR operation circuit(24) performs a by receiving an output and a function failure signal of the NOT circuit(22). The second operation circuit(26) performs an OR logic operation by outputs of the first OR operation circuit(24) and the NOR operation circuit(20). The first delay flip-flop(28) receives an output of the second operation circuit(26) according to a clock signal, and outputs an information about an existing of activity of own board on the case of a variation of the output of the second operation circuit(26). The second delay flip-flop(30) receives an output of the first OR operation circuit(24) according to the clock signal, and outputs an information about an existing of failure of own board on the case of a variation of the output of the first OR operation circuit(24).
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