| 摘要 |
PROBLEM TO BE SOLVED: To provide a call signal detector which detects a call signal by using a signal transmitted from a telephone line or DC without requiring a power supply, and to provide an incoming call apparatus which operates by using a signal transmitted from a telephone line or DC to eliminate the need for the power supply and in which a sound is made to be louder by amplifying a sound signal, and the line is disconnected when opposite equipment is hooked off. SOLUTION: A call signal is rectified, a capacitor is charged with this signal, and a diode is brought into an on state when the charging amount of the capacitor exceeds a prescribed value. The call signal is detected by this diode. COPYRIGHT: (C)2003,JPO
|
