| 摘要 |
PURPOSE:To eliminate an exclusive-use telephone line for a remote control and to attain the remote control even when the call bus control part of a telephone device side is troubled by switching a line mutually the connection with the telephone device and the connection with a remote communication control part. CONSTITUTION:A change-over switch 8 connects always a telephone line L1 to a telephone device side. When a telephone device responds and a receiving detecting circuit 2 and a circuit 4 detects that the designation of the special number by a PB signal detecting circuit 4 is received, or when the condition without detecting the receiving response passes for a prescribed time, the telephone line L1 is switched to a control part 5 side by the switch 8, and a direct current loop circuit is formed by a direct current loop holding circuit 3. Here, the control part 5 responds after the switching of the switch 8, and on condition that the designation of the special number to the telephone device or the control part 5 is detected by the circuit 4, the communication information from the line L1 is received and controlled.
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