| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication equipment capable of promptly stopping the transmission of calling signals in the case that a telephone set is off-hooked while transmitting the calling signals. SOLUTION: The power supply part of this equipment is provided with a calling signal generation part 21 and an off-hook detection circuit 42 by overcurrent detection for detecting current change on the transmission line of pseudo calling signals generated by the calling signal generation part 21 and they are constituted so as to be operated when the telephone set is off- hooked and the line is terminated by DC resistance 50Ω-300Ω. The output of the pseudo calling signals is controlled by a CPU through a photocoupler 40 and off-hook detection signals are transmitted through the photocoupler 41 to the CPU. In the case that off-hook is detected, the CPU immediately stops the output of the pseudo calling signals through the photocoupler 40.
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