| 摘要 |
PURPOSE:To attain sufficiently talking by providing a sound volume control circuit bringing both talking states into a state possible for talking when one device is switched on and controlling the sound volume of a receiver and the gain of a transmitter to each talking circuit even if a called party is located from a location apart from the device. CONSTITUTION:A talk SW15 is switched off in the stand-by state, no power is fed to a transmission section T but power is fed intermittently for, e.g., 5ms at an interval of 2sec to attain intermittent opetation. In depressing the SW15, power is fed for the depressing time to the transmission section T and the reception section R, the talking state is attained, and when a station to be controlled receives intermittently the transmission wave, the carry detection circuit 10 is activated, a carry detection signal is inputted to a power supply/sound volume control circuit 4, a chime tone generating circuit 16 raises chime and also power is fed continuously to the transmission section T and the reception section R at the same time to bring the state to the talking state. Thus, in setting the amplification factor in response to the surrounding state, the response is is attained at a called side without any special operation. |
