| 摘要 |
PROBLEM TO BE SOLVED: To provide a means for detecting contact abnormality of a relay. SOLUTION: A voice communication device 1 has a test means 35 of making a house apparatus A switch a contact of a branch relay in a brancher B with a control signal sent through a control line Lc to transmit a voice signal to a desired house apparatus A and also sending out a predetermined test signal to the house apparatus A through a signal line Ld. In the house apparatus A, a CPU 21 has a function as a detecting means of detecting whether the test means 35 receives the test signal within a previously set test time after sending out the test signal, and reporting that a contact of a relay constituting the transmission line to the voice communication device 1 has abnormality when the test signal is not received. COPYRIGHT: (C)2008,JPO&INPIT
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