Telephone-operated stereo shut-off device

Claim 1

A telephone-operated stereo shut-off device that functions in combination with a telephone set and a stereo receiver operating at least a pair of speakers, said device comprising: A) a telephone/transmitter unit comprising: a) a voltage sensing circuit that is connected to the telephone central office and to the telephone set, where said voltage sensing circuit senses the power levels when either the telephone set rings or the handset is lifted from the telephone-set cradle and produces a first signal, b) a signal inverter/conditioner circuit that receives, inverts and conditions the first signal to produce a second signal, c) a timer/relay circuit that is activated upon receipt of the second signal and produces a timed signal when the telephone set is ringing or lifted off-hook, where the timed signal is used to energize a relay that when energized produces a transmitter enabling signal, d) a transmitting circuit that is connected to a first utility 115 volt a-c power receptacle and that is enabled upon the application of said transmitter enabling signal, where when enabled a coded signal is applied through and along the internal utility power lines, e) a power supply designed to provide the required power levels to operate the circuits of said telephone/transmitter unit, B) a stereo/receiver unit comprising: a) a power input/receiver circuit that is connected to a second utility 115 volt a-c power receptacle and that includes receiver means that is enabled when the coded signal from transmitter means is received via the internal utility power lines, when said enabled receiver produces an a-c power signal, b) a power converter/regulator circuit that receives and converts the a-c power signal to a constant d-c voltage, c) a status display circuit that is operated by the constant d-c voltage and that has the means to sequentially drive a display unit consisting of plurality of indicators that indicate when said stereo/receiver unit is either receiving an incoming call or when the telephone handset has been lifted from the cradle, and d) a speaker muting circuit connected between the stereo receiver and the speakers, where said muting circuit includes a voltage divider network and a relay that is energized by the power signal from said power input/receiver circuit, where when said relay is deenergized the speakers are connected directly to the stereo receiver and conversely, when the relay is energized, the speaker output from the stereo receiver is applied through said voltage divider network which causes the audio signal to be attenuated which then allows the person using the telephone set to have a conversation without interference from the stereo system audio.