| 摘要 |
PURPOSE:To prevent a ringing signal from leaking to an answering person until a ring trip by making a DC loop resistance, when responding to an office trunk, low in value for a certain time and then by temporarily cutting off a channel between ringing transmitting circuits. CONSTITUTION:In response to an incoming call, relay A is operated by set lead S of holding circuit 2 and at the same time, relay C is also put into operation by way of set lead s of holding circuit 3. Then, a channel is shorted via resistance R by the contact of relay C to form a DC loop of low resistance. Consesuently, the ring trip circuit of their station rises quickly. Further, the channel between PBX and their own station is cur off by the contact of relay C and a ringing signal arriving in the operation of relay C is prevented from being heard by an operator. |
