| 摘要 |
PURPOSE:To improve the efficiency of the use of a line by providing a voice/ data identification circuit at exchange side identifying whether a used terminal is a voice terminal or a data terminal and, when a step-out occurs by a ringer from an analog subscriber's line, dropping the line for a data terminal but continueing communication without dropping the line for a voice terminal. CONSTITUTION:Whether a digital subscriber's line 3 is selecting a terminal 10 or a terminal 11, or either in voice data transmission or in data transmission is previously reported to an exchange in a protocal, which is determined by the voice/data identification circuit 25 and also sent to a digital subscriber's control circuit 24. The digital subscriber's control circuit 24 receives outputs from a ringer generation circuit 23, a synchronization monitor circuit 27, and the voice/data identification circuit 25 and, when data is being transmitted on the digital subscriber's line, drops the data line at the occurrence of a step- out by a ringer. On the other hand, during voice transmission with a voice terminal on the digital subscriber's line 3, the digital subscriber's control circuit does not drop the line but continues communication because voice communication is troubled not so much. |
