| 摘要 |
PURPOSE:To make the confirmation of operation of a circuit easy by providing a selecting signal transmission circuit to a main device connected to a bidirectional channel, and transmitting directly a selecting signal transmitted from this circuit at dialing to a main trunk, and transmitting simultaneously said signal to a telephone set side by an amplifier with low impedance. CONSTITUTION:The bidirectional channel 10 is connected to a telephone set line 1 having a handset 4, a main trunk 3 is connected to the channel 10 via a main device 2 to form a transmission signal confirming system. The main device 2 is provided with a selecting signal transmission circuit 5 and a transmission signal control section 41, and the control section 41 consists of a relay switch 143, an analog switch 414, an amplifier 411, an attenuating circuit 412, and a main trunk transformer 415. The switches 413, 414 are driven at dialing, a selecting signal from the transmission circuit 5 is transmitted directly to the main trunk 3 and to the telephone set circuit 1 by a low impedance amplifier 411 at the same time so as to make the confirmation of operation of the telephone device easy. |
