Granted Patent
Utility
US 4,534,043 · App. 06/508,103
Test tone detector apparatus and method modem using same
Inventor:
Vedavalli G. Krishnan
Patented Case
View Patent ↗
Granted: Aug 6, 1985
Filed: Jun 27, 1983
Inventor
Vedavalli G. Krishnan
Assignee (at issue)
Racal Data 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.