Granted Patent
Utility
US 4,390,843 · App. 06/232,703
Telephone system ring period detector
Inventors:
William L. Betts, Kenneth Martinez
Patented Case
View Patent ↗
Granted: Jun 28, 1983
Filed: Feb 9, 1981
Inventors
William L. Betts
Kenneth Martinez
Assignee (at issue)
PARADYNE 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.