Granted Patent
Utility
US 4,412,102 · App. 06/279,262
Key telephone system
Inventors:
Seiki Ogawa, Michio Mito, Tsuyoshi Shinoi
Patented Case
View Patent ↗
Granted: Oct 25, 1983
Filed: Jul 1, 1981
Inventors
Seiki Ogawa
Michio Mito
Tsuyoshi Shinoi
Assignees (at issue)
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Nippon Tsushin Kogyo Kabushiki Kaisha
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.