Granted Patent
Utility
US 4,758,921 · App. 07/017,087
Grounded surge protection unit for telephone subscriber circuits
Inventor:
Peter Hung
Patented Case
View Patent ↗
Granted: Jul 19, 1988
Filed: Feb 20, 1987
Inventor
Peter Hung
Assignee (at issue)
Porta Systems 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.