Record number:       H163570
   Device:              D/T6862
   Model:               M
   Hit count:           UHC00009
   Success count:       USC0000
   Publication code:    PC50
   Tip key:
   Date created:        O98/05/03
   Date last altered:   A98/05/07
   Owning B.U.:         USA

 Abstract:  COM PORT RETRY ERRORS IN WINDOWS 95 AND WINDOWS NT


 SYMPTOM:
 Communication applications return or display COM port
 retry errors (CRC errors, packet errors, terminal window
 character errors) when connecting at data rates of 57kbs
 and higher via external modems.

 PROBLEM ISOLATION AIDS:
 This tip applies to IBM PC300PL Series 6862/6892 systems
 installed with Windows95 or WindowsNT 4.0 and using the
 integrated AGP S3 Trio 3D video adapter.

 This tip also applies to IBM Netfinity 3000 systems in-
 stalled with WindowsNT 4.0.

 The error condition may be seen using an external modem on
 either serial (COM) ports A or B. Internal modems are not
 affected.

 FIX:
 To minimize the likelihood of COM port retry errors, the
 following steps are suggested for Windows95 and WindowsNT:

 Under Windows95, disable "Show window contents while dragging"
 under "Plus!" settings via the following steps:

 1. Right click on the Windows95 desktop, then click on
    Properties.
 2. Click on the Plus! tab. If present, remove the check mark
    from "Show window contents while dragging" and click OK.

 Also under Windows95, reduce the video hardware acceleration
 rate under the video Performance tab via the following steps:
 1. Right click on the Windows95 desktop, then click on
    Properties.
 2. Click on the Settings tab.
 3. Depending on the installed version of Windows95, click on
    the Advanced Properties button, or the Change Display Type
    button.
 4. Click on the Performance tab. Under Hardware Acceleration,
    move the settings slider to the second position, "Basic
    Accelerator functions..." and click OK.

 Under WindowsNT, perform the following steps:

 1. Using the steps outlined above, disable "Show window contents
    while dragging."
 2. Verify "FIFO Enabled" under COM port settings via the fol-
    lowing steps:
    1. Click on Start, Settings, and Control Panel.
    2. Double click on the Ports icon and highlight the
       appropriate COM port. Click on Settings.
    3. Click on Advanced and verify that "FIFO Enabled"
       is checked.

 Windows95 and WindowsNT are trademarks of Microsoft Corporation.

 SAS KEYWORDS:
    CDT                CDTCOMM            CDTOEM             CDTERR
    CDTADPT            D/T6862            D/T6892            6862
    6892               UNCLASSIFIED       84967              84966
    84966F_1           NETFINITY 3000     D/T8476            8476
    84967F_1           84966F_2