Granted Patent
Utility
US 6,069,878 · App. 08/769,965
TDM digital matrix intercom system
Inventor:
Steven G. Christensen
Patented Case
View Patent ↗
Granted: May 30, 2000
Filed: Dec 19, 1996
Inventor
Steven G. Christensen
Assignee (at issue)
Telex Communications, 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.