Granted Patent
Utility
US 4,211,938 · App. 05/951,734
Tone detector
Inventors:
Duane R. Bolgiano, Joel M. Benjamin, Jr., Victor Meyer, Jr.
Patented Case
View Patent ↗
Granted: Jul 8, 1980
Filed: Oct 16, 1978
Inventors
Duane R. Bolgiano
Joel M. Benjamin, Jr.
Victor Meyer, Jr.
Assignee (at issue)
International Mobile 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.