| 摘要 |
<p>PURPOSE:To discriminate power failure of an opposite station by its own station being a reception side by comparing an input terminal voltage of a line receiver of its own station with a voltage comparison band decided by a forward voltage of a diode of the opposite station. CONSTITUTION:When a positive power supply V1 of a power supply of an opposite station is stopped, even if anoutput resistance of a line driver 1 is infinite, a forward current from the positive power supply V3 flows to a diode (D) 4 and a forward voltage drop is generated in the D4. The forward voltage drop is inputted to a window comparator 9 as the input terminal voltage EIN of the line receiver 7 through a cable 2. The comparator 9 compares the voltage EIN with the preset forward voltage drop Vr1 and with the reverse voltage drop Vr2 and a fault signal is outputted as power fault detection of an opposite station 6. If the negative power supply V2 of the opposite station is failed, a fault signal is outputted as the detection of power failure of the opposite station similarly.</p> |
