Importance

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Abstract

A telephone privacy and alerting device for connection between a common telephone line and a telephone device. The privacy and alerting device includes a privacy circuit to prevent the telephone device from accessing the telephone line when another telephone device is already off-hook, and an alerting circuit to indicate an alarm when the telephone device is off-hook and a further telephone device is also off-hook. The privacy circuit includes a voice connecting circuit for connection between the telephone line and the telephone device, a self-latching switch means connected to the voice connecting circuit having an on and off state, and voltage breakdown means for turning the self-latching switch means on when a closed circuit is provided through the telephone device and the potential across said telephone line is above a first predetermined threshold, thereby allowing the voice connecting circuit to establish a current path between the telephone line and the telephone device. The alerting circuit includes alarm means for generating an alarm signal when the alarm means receives a first triggering signal and a second triggering signal simultaneously, current monitoring means responsive to the voice connecting circuit and operatively coupled to the alarm means for providing the first triggering signal when current is present in the voice connecting circuit, and further voltage breakdown means operatively coupled to the alarm means for providing the second triggering signal when the potential across the telephone line is below a second predetermined threshold.

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First Claim