Telephone privacy device

Details Telephone privacy device Telephone privacy device

1975-03-17

1978-02-14

Claffy, Kathleen H.

179 2A, H04M 164

Patent

active

040740781

ABSTRACT:
A device for installation to a telephone which prevents the telephone from ringing except for incoming calls from selected individuals who have been furnished a key device. The key device emits an audible tone into the mouthpiece of the calling telephone which signals the installed device at the called telephone location to accept the call and actuate the called telephone bell or signal. The installed device is connected to the telephone wire of the installed telephone with electronic circuitry that disconnects the ringing current circuit to the installed phone immediately upon the appearance of the ringing current on the phone line, thus preventing ringing of the called telephone bell. The device then sends an electrical signal, which is recognizable as an audible tone, in the receiver of the calling telephone. The authorized caller places the key device adjacent to the mouthpiece of the calling telephone and actuates a switch on the key device to cause it to emit an audible tone, the frequency and duration of which constitutes the recognition signal to the installed device. Failure of the caller to send the proper recognition signal within the pre-set time causes the installed device to clear the telephone line resulting in the calling telephone receiving a dial tone. Upon proper receipt of the recognition signal, the installed device emits an audible signal to the user of the called telephone for a pre-set time period, after which, if the called phone is not answered, the called telephone line is closed to disconnect the circuit.

REFERENCES:
patent: 3061783 (1962-10-01), Noller
patent: 3187108 (1965-06-01), Clin
patent: 3226489 (1965-12-01), Grambsch
patent: 3293371 (1966-12-01), Burns
patent: 3514548 (1970-05-01), De Meo
patent: 3515806 (1970-06-01), Spraker
patent: 3614326 (1971-10-01), Cameron
patent: 3654396 (1972-04-01), Biezeveld
patent: 3784721 (1974-01-01), Kilby
patent: 3793487 (1974-02-01), Kilby
patent: 3859462 (1975-01-01), Saxon

Affiliated with

Also associated with

Rating

Telephone privacy device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Telephone privacy device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone privacy device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-525996