Granted Patent
Utility
US 5,091,933 · App. 07/642,602
Multiple party telephone control system
Inventor:
Ronald A. Katz
Patented Case
View Patent ↗
Granted: Feb 25, 1992
Filed: Jan 17, 1991
Inventor
Ronald A. Katz
Assignee (at issue)
FIRST DATA RESOURCES, LLC.
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.