| 摘要 |
<p>PURPOSE:To efficiently supply a current, by permitting the extension of a power source for a short distance subscriber by number at least equal to the number of surplus subscribers without considering heating in an exchange when a first negative power source for a long distance subscriber has surplus. CONSTITUTION:The telephone set T1 of the long distance subscriber is connected to the negative power source E1 via a subscriber circuit 1, and the telephone set T2 of the short distance subscriber is connected to the negative power source E2 via a subscriber circuit 2. At this time, the chip line and the ring line of the telephone set T3 of a part of the short distance subscribers are connected respectively to the negative terminal of the negative power source E1 and that of the negative power source E2 via a subscriber circuit 3. Also, the circuits 1, 2, and 3 are provided with resistors R1 and R2 for current limitation and current detection on the chip line and the ring line, respectively, and both ends of the resistors R1 and R2 are connected to a current detection circuit, and furthermore, the chip line and the ring line connected to a subscriber line are introduced to a call circuit. In such way, it is possible to house the short distance subscribers equal to the number of surplus subscribers without considering the heating in the exchange when the negative power source E1 has surplus.</p> |
