Granted Patent
Utility
US 6,021,189 · App. 08/957,829
System for controlling usage of phone debit cards
Inventor:
Joe Q. Vu
Patented Case
View Patent ↗
Granted: Feb 1, 2000
Filed: Oct 27, 1997
Inventor
Joe Q. Vu
Assignee (at issue)
Nortel Networks Limited
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.