Granted Patent
Utility
US 4,536,621 · App. 06/608,239
Dual talk path key telephone
Inventors:
Henry Bergen, Sedat Zaimi, Vincenzo Castellano, Irwin Schildkraut
Patented Case
View Patent ↗
Granted: Aug 20, 1985
Filed: May 8, 1984
Inventors
Henry Bergen
Sedat Zaimi
Vincenzo Castellano
Irwin Schildkraut
Assignee (at issue)
IPC Communications, Ltd.
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.