| 摘要 |
PURPOSE:To detect the response of a called party automatically by supervising a calling voice signal of a public telephone network accommodating subscriber and an audible signal of a public telephone network by an exchange of a private network. CONSTITUTION:When a subscriber 4 accommodated in a private network dials a number of a subscriber 8 accommodated in a public telephone network, a communication controller 11 connects a trunk circuit 10 and a response detector 13. When the connection between the subscribers 4 and 8 is finished, a call tone 22 from an audible signal tone generator 16 in a telephone exchange 6 in a public telephone network is transmitted to the subscriber 4 and when the subscriber 8 responds, a voice signal 23 is transmitted respectively. When the device 13 supervises a signal 18 from the public network to the private network and when the call tone 22 is disappeared and the signal 23 appears, it is regarded as a response and the charging to the subscriber 4 is started, and when the subscriber 4 hooks on a handset, the end of call is detected and the charging is finished. |
