Granted Patent
Utility
US 5,870,451 · App. 08/965,360
Method and apparatus for high impedance ringer detection
Inventors:
Richard G. Winkler, Kurt E. Schmidt, David J. Groessl
Patented Case
View Patent ↗
Granted: Feb 9, 1999
Filed: Nov 6, 1997
Inventors
Richard G. Winkler
Kurt E. Schmidt
David J. Groessl
Assignee (at issue)
Teradyne, 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.