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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 <A HREF="ftp://ftp.ast.com/MISC/SERIAL.EXE">SERIAL.EXE</A> 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