| 摘要 |
PURPOSE:To enable a communication means desired by a caller to be used automatically by using one telephone line, by adding a detection circuit that detects a signal different from a call signal, and a control circuit. CONSTITUTION:A switching circuit 11 connects a telephone line 3 to detection circuits 13 and 14 sides during the standby of a call, and connects the telephone line 3 to a data transmission/reception circuit 12 side during a data communication. A control circuit 15, when the detection circuit 13 detects the call signal, instructs the connection of the telephone line 3 to a telephone set 2, to the switching circuit 11, and the detection circuit 13 detects the call signal. Also, when the detection circuit 14 detects a connection control signal, the control circuit instructs the connection of the telephone line 3 to a data transmission/ reception circuit 12, to the switching circuit 11, and at the same time, it instructs the data transmission/reception circuit 12 to start up.
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