Granted Patent
Utility
US 4,731,827 · App. 06/665,681
Interswitch line circuit
Inventor:
Samuel F. Wood
Patented Case
View Patent ↗
Granted: Mar 15, 1988
Filed: Oct 29, 1984
Inventor
Samuel F. Wood
Assignee (at issue)
David 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.