Granted Patent
Utility
US 4,245,325 · App. 06/012,507
Digital multifrequency signalling receiver
Inventors:
Shiro Kikuchi, Hitoshi Imagawa, Yasumasa Iwase
Patented Case
View Patent ↗
Granted: Jan 13, 1981
Filed: Feb 15, 1979
Inventors
Shiro Kikuchi
Hitoshi Imagawa
Yasumasa Iwase
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.