Granted Patent
Utility
US 4,434,669 · App. 06/309,810
Apparatus for transmitting and receiving sound
Inventors:
Victor C. Roberts, Antonio J. Sainz
Patented Case
View Patent ↗
Granted: Mar 6, 1984
Filed: Oct 8, 1981
Inventors
Victor C. Roberts
Antonio J. Sainz
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT 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.