| 摘要 |
PURPOSE:To decrease the rate of generation of ineffective calls and to improve the service without incurring remarkable increase in installation cost, by counting all pulses at a line circuit accommodated at a selection signal main channel network transmitted from various subscriber terminal devices. CONSTITUTION:When a telephone set 70 is a rotary dial type telephone set, a dial pulse transmitted from it is detected at a dial pulse detection circuit 220 of a line circuit 200, counted at a count circuit 230a sequentially and stored in a numeric information storage circuit 240 temporarily. The stored numeric information is transmitted to a central control circuit 60. Further, the telephone set 70 is a push button telephone set, a multi-frequency signal from the telephone set 70 is detected at a multi-frequency signal detection circuit 220b, counted at a counter circuit 230b sequentially, stored in the circuit 240 temporarily and transmitted to the circuit 60. Through the constitution like this, a selection signal transmitted from various subscriber terminal devices such as rotary dial type telephone set and push button telephone set accommodated in a main channel network is counted entirely at the circuit 200 accommodated in the main channel network 10. |
