| 摘要 |
PURPOSE:To prevent malfunction of an exchange by interrupting a channel tentatively during the transmission of a pushbutton dial signal and transmitting no sound signal to the main wire side to prevent a dial pulse and a pushbutton dial signal from being transmitted in mixture. CONSTITUTION:While a pushbutton dial signal is received, a channel breaker control line 17 is activated and a channel 19 is cut off by a channel breaker 16. A pushbutton dial signal decoding section 18 receives a pushbutton dial signal in this case and request a dial pulse output to a dial pulse output section 21 of a main wire interface circuit 13 through a line 20. A dial pulse is transmitted from the dial pulse output section 21 to a main wire 2 through the reception of the request. Thus, no pushbutton dial signal is transmitted to the main wire side and malfunction of an exchange is prevented. |
