| 摘要 |
PURPOSE:To avoid the 1st telephone talking from being limited by a digital link by disconnecting once a telephone communication performed via a non- transmission channel after a specific pushbutton dial signal is converted. CONSTITUTION:When a caller subscriber's controller 13 hooks off, the control circuit 15 executes a call procedure and when a dial input is given, the network is connected to the incoming side. When an incoming side subscriber's controller 13' hooks off, the state is transited to a usual non-transmission telephone talking state. In depressing a changeover key 11 of the controller 13, the circuit 15 drives a PB oscillator 7 to send a button A signal of a PB signal, for example. On the other hand, a signal received by a PB signal receiver 11' in the controller 13' is analyzed by the circuit 15'. The circuit 15' discriminates that the received PB signal is A, enters the switching communication and the oscillator 7' is controlled and a button B signal of the PB signal, for example, is sent.
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