Remotely-controlled loudspeaking telephone - allows bedridden user to answer calls, by pressing transmitting key leaving rest of hands free

摘要

Calls may be taken on a loudspeaking telephone by pressing a key or by a hand-held remote control unit which sends a signal, e.g. ultrasonic or infrared. A receiver for this signal, on the telephone unit, derives its power supply from the incoming ringing voltage. Thus the remote control only operates when the phone is ringing and false operation on interfering signals is minimised. The remote control may have an ON button for taking a call and an OFF button for hanging up, or a single large button for use by a bedridden or handicapped person.