Patents by Inventor Ronald C. Dunbar

Ronald C. Dunbar has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4266101
    Abstract: A telephone switching system, such as a private branch exchange, incorporates a centrally controlled control unit for controlling operation of visual and audible station instrument display device, without interfering with the voice communication line circuits, and without requiring external circuits and equipment.
    Type: Grant
    Filed: July 18, 1979
    Date of Patent: May 5, 1981
    Assignee: Siemens Corporation
    Inventor: Ronald C. Dunbar