Granted Patent
Utility
US 4,245,214 · App. 06/046,346
Switching matrix
Inventor:
Patrick R. Beirne
Patented Case
View Patent ↗
Granted: Jan 13, 1981
Filed: Jun 7, 1979
Inventor
Patrick R. Beirne
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.