Patents Assigned to Telegraph & Telephone Pub. Corp.
  • Control signal transmission system for key telephone system
    Patent number: 4551583
    Abstract: A control signal transmission system for a key telephone system, in which control signal information is transmitted in a parallel signal configuration between a plurality of key telephone sets and a key service unit by the use of transmission lines one-to-one corresponding to the individual key telephone sets, and in which the information between the key telephone sets is transmitted using a serial signal format of a frame configuration so that time slots of respective frames are synchronized with respect to all of the transmission lines.
    Type: Grant
    Filed: March 8, 1984
    Date of Patent: November 5, 1985
    Assignees: Telegraph & Telephone Pub. Corp., Iwasaki Tsushinki Kabushiki Kaisha
    Inventors: Koichi Sekiguchi, Hikaru Takematsu, Kazuyuki Yamamoto, Teruyuki Kubo