Granted Patent
Utility
US 6,229,889 · App. 09/285,670
Robust signaling tone frequency measurement
Inventors:
Joseph M. Cannon, James A. Johanson, Paul Joseph Davis
Patented Case
View Patent ↗
Granted: May 8, 2001
Filed: Apr 5, 1999
Inventors
Joseph M. Cannon
James A. Johanson
Paul Joseph Davis
Assignee (at issue)
Agere Systems Guardian Corporation
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.