Granted Patent
Utility
US 4,254,498 · App. 06/002,208
Time division telephone switching systems
Inventors:
Kanzi Tawara, Kazuo Hamazato, Tatsuro Takahashi, Tetsuaki Egawa
Patented Case
View Patent ↗
Granted: Mar 3, 1981
Filed: Jan 9, 1979
Inventors
Kanzi Tawara
Kazuo Hamazato
Tatsuro Takahashi
Tetsuaki Egawa
Assignee (at issue)
Nippon Telegraph and Telephone Public 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.