Granted Patent
Utility
US 5,682,423 · App. 08/654,185
Electrical power and telephone ringer signal distribution system
Inventor:
David Walker
Patented Case
View Patent ↗
Granted: Oct 28, 1997
Filed: May 28, 1996
Inventor
David Walker
Assignee (at issue)
GPT Limited
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.