Granted Patent
Utility
US 4,741,028 · App. 06/890,644
Method of randomizing telephone numbers
Inventors:
James J. Frimmel, Jr., Alan R. Trefzger
Patented Case
View Patent ↗
Granted: Apr 26, 1988
Filed: Jul 30, 1986
Inventors
James J. Frimmel, Jr.
Alan R. Trefzger
Assignee (at issue)
International Telesystems, 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.