| 摘要 |
PURPOSE:To simplify the constitution of a subscriber circuit (LC), by providing a channel (CH) of the audio signal and a CH of the control signal for fixed connection into a time division network (TD-NW). CONSTITUTION:Both a CH of the audio signal and a CH of the control signal for fixed connection are provided into a TD-MW2 and in correspondence to the subscriber. Thus an LC1 is connected to a digital terminal (DT)4 connected to a digital trunk line 6 via the above-mentioned CHs. The control signal for fixed connection containing a ringing signal, an off-hook signal, an on-hook signal, etc. is inserted along with the audio signal into 1CH once with every 6 frames and at the 8th bit of each CH within the line 6. This control signal is then relayed. A ringing control circuit 25 is controlled in the same way by any control signal given from the TD-NW via a central controller CC3 and the line 6. The detecting signals given from an on/off-hook detecting circuit is delivered in parallel to the CC3 and the TD-NW. |
