| 摘要 |
PROBLEM TO BE SOLVED: To provide a cable disconnect detector which detects disconnection of a cable and contact failures of a connector, in a state where networking equipment are connected by the cable so as to be in a communication enabled state with one another. SOLUTION: In the cable disconnect detector 320, a capacitor C and a secondary winding of a transformer T1a are connected in parallel between a wire 4a and one end of an existing pulse transformer 101, and a capacitor C and a secondary winding of a transformer T1b are connected in parallel, between a wire 4b and the other end of the existing pulse transformer 101. When a low-frequency signal is input from a low-frequency transmitter 30 into a primary winding of the transformer T1a, loop current 13 is excited, and induced current flows in the secondary winding of the transformer T1b. The induced current is detected by a loop current detector 11, thereby detecting that there is neither disconnect of the cable nor contact failure of the connector. In the above operation, the transmitter 30 is controlled, such that the loop current 13 and loop current 15 do not offset each other. COPYRIGHT: (C)2009,JPO&INPIT
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