| 摘要 |
PURPOSE:To attain automatic answering telephone call by bringing the telephone set into the closing state after predetermined number of times of incoming calls in the event of external calling of the automatic answering telephone set if the possessor leaves its home while leaving the setting of standby state undone. CONSTITUTION:If the possessor leaves its home while an operation switch is left set to the 'OFF' position and finds it out at the visiting place, a voltage +B from a battery BAT is not fed to a ringing circuit 1 when operation switches S, Sw-1 are at the 'OFF' position. But the voltage is always supplied to a waveform shaping circuit 20, a counter 21 and a flip-flop 22. Thus, a call signal is counted by the counter 21 and when the count is, e.g., 10 times and a Q output of the counter 21 reaches an H level, the flip-flop 22 is set, its inverse of output Q turns on a power supply switching transistor TR-5. Then the rining circuit 1 reaches the operational state, and telephone lines 11, 12 are brought into the closing state by a call signal coming afterward. Thus, the automatic answering telephone call is attained.
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