Granted Patent
Utility
US 5,832,076 · App. 08/689,219
Apparatus and method for determining the presence and polarity of direct current bias voltage for microphones in telephone sets
Inventors:
James R. Holthaus, David L. Dilley
Patented Case
View Patent ↗
Granted: Nov 3, 1998
Filed: Aug 7, 1996
Inventors
James R. Holthaus
David L. Dilley
Assignee (at issue)
Transcrypt International, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.