Patent: Telephone-responsive Device for Muting the Sound Output of a Television Set

US Patent issued for telephone-responsive device for muting the sound output of a television set. Patent 5,128,987

Apparatus responsive to the operation of a nearby telephone for selectively muting the sound output of a television set, including a ring detection circuit and an off-hook detection circuit coupled in parallel and responsive to either a ringing signal or an off-hook condition of the telephone for delivering an activating signal to a common output, remote-control circuitry selectively operable for muting the sound output of a television set, a controller circuit coupled between the common output and an input of the remote-control circuitry, and manually operated selection switches for providing four different modes of operation. In preferred embodiments the controller includes a plurality of permanently fixed internal logic circuits which respectively correspond to different remote volume control codings of various different makes or models of television sets, and manually operable circuitry are provided for selecting a particular one of the fixed internal logic circuits so as to enable the remote-control circuitry to mute the sound output of a television set whose remote volume control coding corresponds to that praticular fixed logic circuit.