Granted Patent
Utility
US 6,556,664 · App. 09/286,647
Public notification system and method
Inventor:
Al Langsenkamp
Patented Case
View Patent ↗
Granted: Apr 29, 2003
Filed: Feb 3, 1999
Inventor
Al Langsenkamp
Assignee (at issue)
Sigma 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.