Granted Patent
Utility
US 6,694,010 · App. 09/299,604
Recognition of a single frequency tone
Inventor:
Eric Verreault
Patented Case
View Patent ↗
Granted: Feb 17, 2004
Filed: Apr 27, 1999
Inventor
Eric Verreault
Assignee (at issue)
Alcatel Canada 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.