Granted Patent
Utility
US 4,782,523 · App. 07/043,053
Tone detection process and device for implementing said process
Inventors:
Claude Galand, Guy Roulier, Robert Vermot-Gauchy, Helene Cerf-Danon
Patented Case
View Patent ↗
Granted: Nov 1, 1988
Filed: Apr 27, 1987
Inventors
Claude Galand
Guy Roulier
Robert Vermot-Gauchy
Helene Cerf-Danon
Assignee (at issue)
International Business Machines 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.