Granted Patent
Utility
US 6,256,491 · App. 09/001,953
Voice security between a composite channel telephone communications link and a telephone
Inventors:
Douglas E. Ehlers, Christopher A. Hall, James R. Holthaus
Patented Case
View Patent ↗
Granted: Jul 3, 2001
Filed: Dec 31, 1997
Inventors
Douglas E. Ehlers
Christopher A. Hall
James R. Holthaus
Assignee (at issue)
Transcrypt International, 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.