| 摘要 |
PURPOSE:To attain sure operation in conducting remote control with a telephone line by pulsing a ringing tone of a telephone set and counting the pulses. CONSTITUTION:If one finds out at a visiting place that one left home without turning, e.g., gas off at the main cock, a ringing tone is inputted to a microphone 61 continuously for a prescribed number of times or over through the telephone line then a signal is counted in a count circuit 65 at each one intermittent sound and the same signal is also fed to a monostable vibrator circuit 66. When a handset of the visiting place is hooked on after a call tone is generated for a prescribed number of times or over in order to shut the main cock, since the ringing tone is interrupted, the circuit 66 is operated, a reset signal is applied to the counter circuit 65, which is restored to the initial state. |
