Granted Patent
Utility
US 4,293,737 · App. 06/100,949
Ringing decoder circuit
Inventor:
Jacob Cepelinski
Patented Case
View Patent ↗
Granted: Oct 6, 1981
Filed: Dec 6, 1979
Inventor
Jacob Cepelinski
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.