Granted Patent
Utility
US 4,386,240 · App. 06/214,409
Push-button unit for telephone sets
Inventors:
Gerd Philipp, Manfred Ramsaier, Albert Schach
Patented Case
View Patent ↗
Granted: May 31, 1983
Filed: Dec 8, 1980
Inventors
Gerd Philipp
Manfred Ramsaier
Albert Schach
Assignee (at issue)
International Standard Electric Corporation
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.