Granted Patent
Utility
US 5,949,873 · App. 08/833,426
Method of providing centrex type operation using a PBX and a central switching office
Inventor:
Deborah L. Pinard
Patented Case
View Patent ↗
Granted: Sep 7, 1999
Filed: Apr 7, 1997
Inventor
Deborah L. Pinard
Assignee (at issue)
Mitel 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.