Abstract: 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.