    AST RESEARCH, INC.                TECHNICAL BULLETIN #0892            2-16-94

                                POWER EXEC CRC ERRORS

    PROBLEM:       During serial port communications at speeds greater than 9600
                   baud, CRC errors occur every twenty seconds.

    CAUSE:         The SL architecture required that the power management design
                   implement a "heart-beat" whereby interrupts are disabled for
                   about 600us every twenty seconds.  This allows the Power
                   Management (PM) to communicate with the Keyboard Controller
                   (KBC).  When communications programs operate at higher baud
                   rates, they can drop data during this 600us period.  Some
                   programs, such as Laplink 5, have incorporated automatic
                   retries in case of an error.  Others, such as Procomm for
                   Windows, do not, as yet, have this.

    SYSTEMS
    AFFECTED:      Power Exec

    SOLUTION:      There is no resolution at this time.  Future products will not
                   have this "heart-beat" problem.