| 摘要 |
<p>PURPOSE:To make the power consumption at incoming call and howler state equal to that at communication and calling state, by stopping power supply to a CODEC and a call circuit at incoming call and howler state, and supplying a part of the power to a calling circuit, in a digital telephone set. CONSTITUTION:A monitor circuit 24 activates the power supply of power supply communication circuits 21, 23 other than the calling and howler state, stops the power supply to a power supply control circuit 22, a communication circuit 12 and a CODEC 10 are activated and a call circuit 11 is stopped. Since a calling signal is transmitted with the presence of an incoming call, this is interpreted at a signal control section 9, an instruction is given to the monitor circuit 24 and the circuit 11 to invert the operation of the control circuits 21 23. Thus, a call tone rings in the circuit 11 according to a tone indication signal from the circuit 9. When a called party responds, an off-hook signal is given from the circuit 9 to the circuit 24, resulting that the control circuit 21 23 are restored to the original state. If on-hooking is not done after the call, the power supply control for howler detection is done.</p> |
