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AST RESEARCH, INC.          TECHNICAL BULLETIN #0147                  1-13-95

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               ASCENTIA 900N EASYPORT II AND EXTERNAL PS/2 MOUSE


PROBLEM:        While connected to an EasyPort II, the Ascentia 900N system
                may not recognize an external PS/2 mouse.  If the Ascentia
                900N is powered down and a printer is left with power on, the
                next time that power is applied to the Ascentia 900N, the
                external mouse fails to be recognized (intermittently), and the
                integrated pointing device becomes available instead.

CAUSE:          There is a voltage leak on the EasyPort II caused when the
                printer attached to the EasyPortII is ON.  The leakage occurs
                in the DOCKER CHIP location U6 (AST P/N 239020-001), as well
                as the HC125 drivers in locations U4 and U7 of the
                EasyPort II.  When this leakage occurs, there is about 2.0V on
                the EasyPortII as well as in the Ascentia 900N.

                The Hardware Mouse (PS/2 type) performs its internal reset via
                the +5V (power) line.  The reset depends on the +5V supply to
                go from ground to +5V (+/- 10%). The "GROUND" level should be
                no higher than 1.0V / 1.2V, to guarantee proper hardware reset
                to the mouse hardware.

SYSTEMS
AFFECTED:           AST
                PART NUMBER     DESCRIPTION

                500974-XXX      EASYPORT II

SOLUTION:       Do not leave the printer ON when the Ascentia 900N is turned
                off while connected to the EasyPort II.