Granted Patent
Utility
US 5,164,923 · App. 07/772,898
Cumulative operational timers and methods for cellular telephones
Inventor:
Graham M. Avis
Patented Case
View Patent ↗
Granted: Nov 17, 1992
Filed: Sep 26, 1991
Inventor
Graham M. Avis
Assignee (at issue)
Hughes Aircraft Company
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.