| 摘要 |
PURPOSE:To simplify the circuit constitution of a subscriber's terminal by sending audible signals in time series, by selecting an audible signal to be sent out according to a state to be reported, and by changing the transmission time and repetitive period of the selected signal. CONSTITUTION:In starting time T1 of repetitive period T, control circuit 5 makes selecting circuit 4 select the output of audible signal generator 1. In the next time T2, the output of audible signal generator 2 is selected and in the further following time T3, the selection of circuit 4 is inhibited to eliminated its output. Therefore, the signal shown in the figure appears at output 6 of circuit 4. Thus, the circuit constitution of the subscriber's terminal can be simplified. |
