Granted Patent
Utility
US 4,543,664 · App. 06/110,873
Direct current coupled data transmission
Inventor:
Philip R. Couch
Patented Case
View Patent ↗
Granted: Sep 24, 1985
Filed: Jan 10, 1980
Inventor
Philip R. Couch
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.