Granted Patent
Utility
US 4,891,806 · App. 07/098,547
Constellation multiplexed inband secondary channel for voiceband modem
Inventors:
Luis Farias, Vadavalli G. Krishnan, Chin Wong
Patented Case
View Patent ↗
Granted: Jan 2, 1990
Filed: Sep 18, 1987
Inventors
Luis Farias
Vadavalli G. Krishnan
Chin Wong
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.