Patents by Inventor Yoshihisa Shibayama

Yoshihisa Shibayama 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).

  • Electronic key telephone system
    Patent number: 4236049
    Abstract: A key telephone system includes among other things a central switching network comprises of a main switch matrix including main talking paths and trunk paths, an auxiliary switch matrix including auxiliary talking paths and a coupling matrix between the main and auxiliary switch matrices and in which system each of the telephone station sets can talk through a plurality of talking paths, concurrently, and is capable of talking back hand-free.
    Type: Grant
    Filed: December 26, 1978
    Date of Patent: November 25, 1980
    Assignee: Nippon Electric Co., Ltd.
    Inventors: Ryoichi Tanihata, Tsunehiko Shimazawa, Yoshihisa Shibayama