Granted Patent
Utility
US 4,496,799 · App. 06/448,978
Handsfree telephone instrument using digital dial
Inventors:
Rickey W. Kingen, Robert Hume Duncan
Patented Case
View Patent ↗
Granted: Jan 29, 1985
Filed: Dec 13, 1982
Inventors
Rickey W. Kingen
Robert Hume Duncan
Assignee (at issue)
International Telephone and Telegraph 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.