Capacitive proximity sensors
Circuit arrangement for a voice-controlled hands-free telephone
Circuit arrangement for controlling the volume range of a voice
Circuit for hands free talking
Circuit for suppressing white noise in received voice
Class `D` audio speaker amplifier circuit with state variable fe
Communication terminals with a dual use speaker for sensing...
Conference telephone system and method
Conference telephone using dynamic modeled line hybrid
Control circuit for mobile telephone with full duplex operation
Control circuit having a direct current control loop for control
Control device for a hand-free alternate operating telephone set
Control device for a hands-free telephone set
Conversion of compressed speech codes between attenuated and una
Current switch for use in telephony systems or the like