Granted Patent
Utility
US 4,644,476 · App. 06/625,934
Dialing tone generation
Inventor:
Lawrence E. Bergeron
Patented Case
View Patent ↗
Granted: Feb 17, 1987
Filed: Jun 29, 1984
Inventor
Lawrence E. Bergeron
Assignee (at issue)
Wang Laboratories, 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.