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    AST RESEARCH, INC.       TECHNICAL BULLETIN # 0950A                 3-10-95

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    		WINDOWS AND PENTIUM-BASED SYSTEMS WITH A 16550 UART CHIP

    PROBLEM

    When using Windows version 3.11 with serial communications software,
    the following problem may occur:

    Using a Pentium-based machine with a 16550 UART chip, when the serial
    communications application attempts to open the communications port, the system
    may stop responding (hangs) if there is data in the chip.

    CAUSE

    A problem with the 16550 UART implementation causes the chip to become trapped
    in a mode in which data is always detected in its FIFO buffer.

    SYSTEMS AFFECTED

    All Pentium-based systems with a 16550 UART chip.

    SOLUTION

    Download file SERIAL.EXE from AST's BBS "Systems" file area, and follow the
    README file instructions.  File WG1001, contained in SERIAL.EXE, includes an
    updated SERIAL.386 driver that corrects the problem.

    AST's BBS can be reached by dialing (817) 230-6850.  AST's BBS supports modem
    speeds up to 28.8k bps.  The above file will also be posted on:

    CompuServe
    Go ASTSUPPORT

    AST Worldwide Web Site
    http://www.ast.com