PURPOSE: To display the state of a telephone set to a caller without harming the miniaturization of the telephone set, by displaying a transmitting or receiving state and the closing state of a transmission level signal together.
CONSTITUTION: When an output from a microphone 1 is desired to be closed temporarily, a microphone switch 13 is operated. A display 16 is energized via a contact 13-3 so as to alarm to a caller that the transmission signal is closed. When an output from the microphone 1 is applied to an amplifier 2, the contact 3-3 is connected to an output of a comparator 10. The display 16 is connected to an output of the comparator 10 to a receiving variable loss circuit 7. The display 16 is energized with a control signal decreasing the loss of the receiving variable loss circuit 7 and displays that the loudspeaker telephone set is set in the receiving state to the caller.
TAKAYAMA TAKUMI
SUDOU YOUZOU
