Patents by Inventor Mikihiro Ichikawa

Mikihiro Ichikawa 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).

  • Control circuitry for key telephone apparatus
    Patent number: 4081625
    Abstract: The disclosure is for key telephone system line control circuitry which provides telephone station line status signals for central office ring, busy, idle and station hold conditions by means of a single control line.
    Type: Grant
    Filed: October 1, 1976
    Date of Patent: March 28, 1978
    Assignees: Nippon Tsu Shin Kogyo K.K., TIE/Communications, Inc.
    Inventors: Fumikazu Hamatani, Mikihiro Ichikawa, Yuji Tanaka