| 摘要 |
<p>PURPOSE:To detect not only the trouble of an interface cable, but also the power-off state of a corresponding communication equipment by connecting a specific logic circuit provided to one communication device to the trouble detection part of the other communication device through an interface cable. CONSTITUTION:One communication equipment 1A among communication equipments 1A, 1B is provided with the trouble detection part 4A which has a pull-up resistance 5A at the input part and the other communication equipment 1B is provided with the logic circuit 7B which is connected to the trouble detection part 4A through the signal line 21 in the interface cable 2. The logic circuit 7B is constituted as a logic circuit which enters a high-impedance state by the power-off operation of the communication equipment 1B while generating a low-level output when the power source 6B of the communication equipment 1B is normal. Consequently, not only the trouble of the interface cable 2, but also the power-off state of the corresponding communication equipment can be detected.</p> |
