Abstract: An intercom system having a pair of interconnected devices, each of which has a speaker, a tap transducer, a power source and switch means, so that when they are connected together electrically, each device may be used as a transmitter or as a received, with the tap transducer in each case forming part of an electrical circuit serving both to receive and transmit signalling and sound signals, such as voice or other speech sounds. A detection device is provided for insuring that the intercom operates in that orientation thereof which provides optimum operating characteristics.

Abstract: This invention describes an electromechanical sound apparatus which can be utilized as part of a sound system such as an intercom or as an acoustic repeater. The apparatus includes a loudspeaker having a diaphragm and a coil. The coil receives variations of electric energy and causes the diaphragm to vibrate. An electromechanical sound (sensor/microphone) transducer is connected to the loudspeaker. The transducer includes conductive supports mounted onto the loudspeaker diaphragm and a weighted conductive bar loosely coupled to the supports. Electric energy is connected across the conductive supports. As the diaphragm vibrates, the vibrations are transmitted through the conductive supports to the bar, which interrupts the electrical energy and converts the vibrations into electrical energy variations. The loudspeaker diaphragm can be utilized to directly receive acoustic energy for the transducer, or as a standard loudspeaker output unit.

Abstract: This invention describes an electromechanical amplifying sound transducer including a diaphragm which responds to input energy, such as acoustical waves and mechanical pulses, and vibrates in response thereto. Conductive supports mounted onto the diaphragm are adapted to be interconnected to a source of electrical energy. A weighted conductive bar is loosely coupled to the supports and interconnects them. The supports transmit the vibrations to the bar whereby the bar can control the electrical energy delivered from the source of electrical energy so that the acoustic waves or mechanical pulses are converted into amplified electrical waves.

Abstract: A vibration transducer, comprising a conductive member, such as a weighted carbon bar loosely fitting into support means, such as a pair of carbon bearing blocks with the bearing blocks rigidly attached to a flexible membrane, serves as the transmitter of the voice transmission system. The bearing blocks are series wired into an electrical circuit, including a direct-current power source and a loud-speaker coil. A fluctuating pressure signal sets the flexible membrane into vibration and causes the weighted carbon bar to bounce in its bearings, thereby alternately interrupting and closing the electrical circuit. The pulsed DC signal passing through the loud-speaker coil reproduces the motion experienced by the transducer membrane in the motion of the loud-speaker cone thereby reproducing the input sound pattern.