Granted Patent
Utility
US 5,202,883 · App. 07/386,697
Digital key stystem architecture
Inventors:
Richard A. Hatherill, Bernard J. Trudel, Mark R. Coomber, William C. Mitchell
Patented Case
View Patent ↗
Granted: Apr 13, 1993
Filed: Jul 31, 1989
Inventors
Richard A. Hatherill
Bernard J. Trudel
Mark R. Coomber
William C. Mitchell
Assignee (at issue)
Mitel 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.