Granted Patent
Utility
US 5,017,917 · App. 07/292,295
Restriction of communication service accessibility among subscriber communities
Inventors:
Thomas S. Fisher, Martin R. Losty
Patented Case
View Patent ↗
Granted: May 21, 1991
Filed: Dec 30, 1988
Inventors
Thomas S. Fisher
Martin R. Losty
Assignee (at issue)
AT&T Bell Laboratories
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.