| 摘要 |
<p>PURPOSE:To eliminate deterioration of unbalance attenuation by inserting a diode into both wires of two cable core wires which supplies DC to a subscriber's circuit terminating set. CONSTITUTION:A station power supply circuit has diodes 42-1, 42-2, 43-1 and 43-2 inserted into both ends of the two core wires comprising balance cables (interface wires 6 and 7) in a DC power supply system inside a subscriber's circuit terminating set 2. When a subscriber's device 4 is under a communication condition, a switch 32 is on, and when a switch 33 is off under the condition of a subsriber's device 5 awaiting a call, DC flows the diodes 42-1 and 42-2 but DC does not flow to the diode 43-1 or 43-2, thereby enabling elimination of deterioration of the unbalance attenuation.</p> |
