| 摘要 |
PURPOSE:To attain effective use of a multiple frequency signal by constituting the system that a multiple frequency signal receiver is connected via a digital switch during talking connection between a private telephone exchange and a public telephone network so as to supervise the multiple frequency signal. CONSTITUTION:When an incoming call comes from a subscriber interface section CO1 of a public telephone network to a private exchange, a microprocessor muP detects it and reports it to an exchange controller CP. The CP acquires a selection signal reception circuit IBT, receives a called party number, calls the called party S so as to form a channel between the CO1 and the called party S when a response comes. In this case, the CP commands the supervision of the multiple freqeuncy signal during talking to the muP via a signal buffer circuit BUF. The muP controls a digital switch SVNW so as to form a channel between the CO1 and a multiple frequency signal receiver PBR. Thus, the reception data of the multiple frequency signal is supervised by the muP even during talking. |
