Granted Patent
Utility
US 4,742,537 · App. 06/870,506
Telephone line monitoring system
Inventor:
Robert Jesurum
Patented Case
View Patent ↗
Granted: May 3, 1988
Filed: Jun 4, 1986
Inventor
Robert Jesurum
Assignee (at issue)
Electra Information Systems, 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.