Granted Patent
Utility
US 6,594,274 · App. 09/246,725
Detection circuit for detecting state of use of B channel and ISDN terminal using the same detection circuit
Inventor:
Hirofumi Ohyama
Patented Case
View Patent ↗
Granted: Jul 15, 2003
Filed: Feb 9, 1999
Inventor
Hirofumi Ohyama
Assignee (at issue)
NEC INFRONTIA 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.