| 摘要 |
PROBLEM TO BE SOLVED: To reduce the current consumption at call waiting time by outputting a power-off signal to a switch terminal for controlling power supply at the call waiting time and cutting off the power supply from the power source to a microphone. SOLUTION: A CPU 3 outputs a control signal '1' during a telephone call to turn on the switch element 2 and supply the voltage from the power source to the microphone 1. At the waiting time, a control signal '0' is outputted to the switch element 2, which is turned off to cut off the power supply to the microphone 1. The CPU 3 outputs a control signal for resetting the power- off state to the switch element 2 when an opposite subscriber is called to turn on the switch element 2 and then supply the electric power to the microphone 1, thereby making the telephone set ready for a telephone call. When an on-hook key is pressed at on-hooking time, a power-off control signal is outputted to the switch element 2, which is turned off to cut off the power supply to the microphone 1. |
