Granted Patent
Utility
US 4,309,578 · App. 06/157,507
Telephone ringer load simulator
Inventor:
Om Ahuja
Patented Case
View Patent ↗
Granted: Jan 5, 1982
Filed: Jun 9, 1980
Inventor
Om Ahuja
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.