Granted Patent
Utility
US 4,225,935 · App. 05/830,274
Coding method and system with enhanced security
Inventors:
John W. Zscheile, Jr., Billie M. Spencer
Patented Case
View Patent ↗
Granted: Sep 30, 1980
Filed: Aug 30, 1977
Inventors
John W. Zscheile, Jr.
Billie M. Spencer
Assignee (at issue)
Sperry Corp.
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.