Granted Patent
Utility
US 6,657,994 · App. 09/383,167
Uninterrupted transfer of voice telephony service to derived voice technology
Inventor:
Yasantha Rajakarunanayake
Patented Case
View Patent ↗
Granted: Dec 2, 2003
Filed: Aug 25, 1999
Inventor
Yasantha Rajakarunanayake
Assignee (at issue)
Covad Communications Company
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.