Telephone call screening apparatus

DETAILED DESCRIPTION Such problem is overcome according to the invention in one of its aspects by providing apparatus which is designed for use at a telephone set station to screen telephone calls incoming thereto over telephone lines from a central office, and which apparatus comprises: source means of electric tone signals, transducer means to convert such signals to audible ringing tones, gate means coupled between said source and transducer means to transfer said signals from the former to the latter, delay means adapted on being triggered to disable such gate means for a period from transferring such signals, call answering means responsive to ringing current on said lines signaling a call to said station to trigger said delay means to start said period and to make a connection providing a path for transmission of said call to said station, Touch Tone (TT) signal detector means responsive to a special TT signal transmitted over said path and applied during said period by the sender of said call and designating it as being in a specified category to produce an indication of receipt at said station of said TT signal, and call terminating means responsive to said indication to break said connection so as to signal said office that said call is rejected and to automatically terminate said call at said station without there being audible ringing thereat.
According to the invention in another of its aspects, such apparatus comprises call answering means to signal the central office of completion of a call, the mentioned TT signal detector means, the mentioned call terminating means for automatically terminating the call if the call is designated by receipt of a TT signal as being in a specified category, and responder means operable upon such receipt to transmit to the sender of the call a return signal adapted to inform the sender that the call has been received and rejected.