DOCUMENT:Q110568 26-SEP-1999 [win95x] TITLE :Pentium-Based Machine Hangs with Communication Applications PRODUCT :Microsoft Windows 95.x Retail Product PROD/VER:WINDOWS:3.1,3.11 OPER/SYS: KEYWORDS:win31 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows versions 3.1, 3.11 - Microsoft Windows for Workgroups versions 3.1, 3.11 ------------------------------------------------------------------------------- SYMPTOMS ======== Pentium-based machines with a peripheral component interface (PCI) bus and a 16550 UART chip stop responding (hang) or exhibit other unexpected behavior when you use communication applications, such as Microsoft At Work PC Fax or Microsoft Terminal. In some cases, you may be able to run the software successfully once but then experience problems when you try to run it a second time (before Windows is restarted). CAUSE ===== The PCI bus uses a new universal asynchronous receiver transmitter (UART) chip that identifies itself as a 16550 chip but does not handle the 16-bit buffer the same way that the 16550 UART chip does. These problems occur if there is data in the chip when the serial communications application attempts to open the communications port. A problem with the chip implementation causes the chip to become trapped in a mode in which data is always detected in its FIFO buffer. The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability. Additional query words: appnote 3.11 3.10 3.1 gateway2000 exit restarted gateway Dell XPS AMI motherboard kit machine built-in com comm port ports NEC Image 466ES PCs print Remote Access Services ====================================================================== Keywords : win31 Technology : kbAudDeveloper kbWin3xSearch kbWFWSearch kbZNotKeyword3 kbWin310 kbWin311 kbWFW310 kbWFW311 Version : WINDOWS:3.1,3.11 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.