Granted Patent
Utility
US 5,204,861 · App. 07/672,032
Key telephone system with enhanced connectivity
Inventor:
Charles Richard Wiebe
Patented Case
View Patent ↗
Granted: Apr 20, 1993
Filed: Mar 19, 1991
Inventor
Charles Richard Wiebe
Assignee (at issue)
Nortel Networks Limited
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.