| 摘要 |
A telephone communication enable state maintaining circuit is disclosed, and the circuit includes a communication circuit 10, a communication operating circuit 20 and an operation maintaining circuit 30. The communication circuit 10 includes contacts 3,4,5, and a condenser C1. The communication operating circuit 20 includes a resistor r1, a condenser C2, a transistor 6 and contacts R3a, R3b, R1a, R1b. The operation maintaining circuit 30 includes contacts R1c, R3c, a resistor r2, a condenser C3, and a transistor 7. According to the present invention, telephone calls from the outside can be received, even if the telephone receiver is placed in an abnormal manner.
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