| 摘要 |
PURPOSE:To decrease a whole switch and to make it common by using a non- bias action two-ways switch for a common switch and a switch for testing of a subscriber line and transferring an alternating current signal through a two-way feeding circuit. CONSTITUTION:A non-bias action two-way switch is used respectively for a common switch 16 of a subscriber line, a switch 17 for a ring and a switch 20 for testing. In the two-way feeding circuit 15, a normal feeding or a reverse feeding are designated, a call electric current is supplied and the electric potential of an A line and a B line is inverted. In the reverse feeding condition of the circuit 15, the switches 16 and 17 are turned on and a direct current electric potential is supplied from a main power source 1 to a terminal 4 and a call signal from a signal source 6 is transmitted. Further, a subscriber condition is tested by turning on the switches 20 and 16 and connecting a testing device. |
