Granted Patent
Utility
US 5,787,115 · App. 08/579,967
Key telephone system without common control
Inventors:
Robert Turnbull, David Westergaard, Bruce W. Yee, Michael J. Lucas, Alan D. Eyre, Brian McKinney
Patented Case
View Patent ↗
Granted: Jul 28, 1998
Filed: Dec 28, 1995
Inventors
Robert Turnbull
David Westergaard
Bruce W. Yee
Michael J. Lucas
Alan D. Eyre
Brian McKinney
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.