1
Frederick M Kruger: Two active element in-the-ear microphone system. Greer Burn & Crain, November 25, 1997: US05692059 (205 worldwide citation)

The herein described invention relates to an ear mounted, in-the-ear compound microphone system which simultaneously uses both an accelerometer, or vibration transducer, to sense bone conducted low speech frequencies and a microphone with controlled frequency response to sense airborne high speech f ...


2
Frederick M Kruger, Richard Leifer: Method and apparatus for screening telephone calls in response to an answering device beep tone. Richard Leifer, Collard & Roe P C, June 16, 1998: US05768344 (3 worldwide citation)

A remote audio monitor for use with a telephone answering device connected to a common telephone line enables the screening of an incoming telephone call from a remote location with respect to the answering device. The remote audio monitor monitors the changing DC voltage levels of the telephone lin ...