Granted Patent
Utility
US 4,943,958 · App. 07/044,858
ISDN interface trunk circuit
Inventors:
John Stewart Young, Peter Kruis, William D. Blewitt
Patented Case
View Patent ↗
Granted: Jul 24, 1990
Filed: May 1, 1987
Inventors
John Stewart Young
Peter Kruis
William D. Blewitt
Assignee (at issue)
Communications 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.