KEYBOARD INTERFACE SYSTEM
    4.
    发明专利

    公开(公告)号:CA1205206A

    公开(公告)日:1986-05-27

    申请号:CA448059

    申请日:1984-02-22

    Applicant: IBM

    Abstract: KEYBOARD INTERFACE SYSTEM A keyboard interface for a data processing system in which a keyboard and a data processing unit are connected through a single clock line for transmitting a keyboard out clock signal and a single data line for transmitting a serial bit frame having a serial scan code identifying a depressed key in synchronism with the clock signal is disclosed. The interface uses a transmission error detection and resend procedure to prevent transmission error due to noise pulse induced on the clock line as by electrostatic discharge to give rise to extra data sampling. The unit returns a status signal acknowledging the receipt of a frame to the keyboard through the data line imeediately after the number of sampled bits received by the unit reaches the predetermined number of bits of a frame. The keyboard checks whether the status signal has been returned after the completion of transmission of a frame and, if not, returns a negative response to the unit through the clock line, then resending the same scan code. The interface permits the use of a low cost, low noise-tolerance stretch cable without shield.

    7.
    发明专利
    未知

    公开(公告)号:BR9503840A

    公开(公告)日:1996-09-10

    申请号:BR9503840

    申请日:1995-08-30

    Applicant: IBM

    Abstract: The present invention relates to a resilient hollow grip cap for removable mounting on the top of a computer control device i.e., a finger actuated pointing stick. The cap has a plurality of short fibers adhered to its outer surface and extending outwardly away from the surface of the cap.

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