Granted Patent
Utility
US 4,890,317 · App. 07/301,347
Automatic validation of telephone account numbers
Inventors:
John A. Hird, Lindsey D. Owen, Michael R. Rice
Patented Case
View Patent ↗
Granted: Dec 26, 1989
Filed: Jan 23, 1989
Inventors
John A. Hird
Lindsey D. Owen
Michael R. Rice
Assignee (at issue)
Intellicall, Inc.
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.