Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
345 words
A privacy circuit adaptable for installation to the incoming lines of a called telephone connected through a conventional telephone exchange which signals an incoming call only if the calling party generates an audible recognition signal through the mouthpiece of the calling telephone, said device inhibiting the sounding of the conventional bell of the attached called telephone for all incoming calls, without requiring detachment of the circuity of said bell, said privacy circuit comprising a first circuit connected to the incoming lines of the called telephone, said first circuit including electronic means to sense and to inhibit an incoming ringing signal and prevent ringing of the attached bell of the called telephone, said electronic means of said first circuit including electronic circuit means to immediately reduce the voltage across the incoming called telephone line so as to simulate the answering of the called telephone, upon sensing an incoming ringing signal and before the bell of the called telephone can be actuated by the ringing signal, with said reduction of voltage across the line of the called telephone causing the central telephone exchange to discontinue the ringing signal prior to actuation of the attached bell of the called telephone, and a timer circuit which holds said first circuit in the sensed condition for a pre-set period of time after the first circuit inhibits the ringing signal, a first oscillator circuit at the called telephone which sends a signal recognizable as an audible tone to the receiver of the calling telephone, a recognition circuit at the called telephone which is responsive to the receipt of said tone signal generated by the calling party having a specific frequency and specific time duration, for energizing a second oscillator circuit to generate an audible signal through an attached first loudspeaker at the called telephone, said second oscillator circuit controlled by the said timer to remain operative for a pre-set period, said first circuit, when de-energized by the said timer circuit acting to clear the incoming telephone line of the called telephone so that the caller is disconnected from the called line.
Claim 2
Dependent Claim
345 words
A privacy circuit adaptable for installation to the incoming lines of a called telephone connected through a conventional telephone exchange which signals an incoming call only if the calling party generates an audible recognition signal through the mouthpiece of the calling telephone, said device inhibiting the sounding of the conventional bell of the attached called telephone for all incoming calls, without requiring detachment of the circuity of said bell, said privacy circuit comprising a first circuit connected to the incoming lines of the called telephone, said first circuit including electronic means to sense and to inhibit an incoming ringing signal and prevent ringing of the attached bell of the called telephone, said electronic means of said first circuit including electronic circuit means to immediately reduce the voltage across the incoming called telephone line so as to simulate the answering of the called telephone, upon sensing an incoming ringing signal and before the bell of the called telephone can be actuated by the ringing signal, with said reduction of voltage across the line of the called telephone causing the central telephone exchange to discontinue the ringing signal prior to actuation of the attached bell of the called telephone, and a timer circuit which holds said first circuit in the sensed condition for a pre-set period of time after the first circuit inhibits the ringing signal, a first oscillator circuit at the called telephone which sends a signal recognizable as an audible tone to the receiver of the calling telephone, a recognition circuit at the called telephone which is responsive to the receipt of said tone signal generated by the calling party having a specific frequency and specific time duration, for energizing a second oscillator circuit to generate an audible signal through an attached first loudspeaker at the called telephone, said second oscillator circuit controlled by the said timer to remain operative for a pre-set period, said first circuit, when de-energized by the said timer circuit acting to clear the incoming telephone line of the called telephone so that the caller is disconnected from the called line.
Claim 3
Dependent Claim
47 words
The circuit described in claim 1 in which the privacy circuit is fitted with optical coupling means for connection of the first said circuit to the external line of the said called telephone so as to otherwise isolate the privacy circuit from the said external telephone line.