| 摘要 |
PURPOSE:To calculate the detected number of the specified level and discriminate the presence and absence of the calling signal exactly based on the result of the calculation by detecting the presence and absence of the calling signal and sampling the level of the output signal. CONSTITUTION:A control signal from a calling signal detecting circuit 108, trunk line loop monitoring circuit 109, hybrid circuit 101, insertion/extraction circuit 103 is extracted into a trunk circuit 100 of an exchange system, and a CPU 104 is provided to control each circuit. Further, a scanning circuit 107 to obtain a state signal from each circuit, distributing circuit 106 to distribute a control signal to each circuit, memory 105 are provided to connect a switch 111 with a circuit 103. The change of voltage of the calling signal from a change CO is detected by a detecting circuit 102 of the circuit 100, and the signal level is sampled by a CPU 104 for the specified period to calculate the number of detecting and discriminate the presence or absence of the calling signal exactly based on the result of the calculation. |
