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Service Hints & Tips |
Document ID: JBAR-3U6JAM |
Cross Brand - COM port overrun errors in Windows 95 and Windows NT
Applicable to: World-Wide
Symptom
Communication applications return or display COM port errors (CRC errors, packet errors, overrun data, terminal window character errors) when connecting at data rates of 57kbs and higher via external modems.
Problem isolation aids
This tip applies to the following IBM machine types pre-installed with Windows 95, Windows 98 or Windows NT 4.0, and using the integrated S3 Trio 3D AGP video adapter.
IBM PC300PL Series 6862/6892 systems
IBM PC300GL Series 6275/6285 systems
This tip may also apply to IBM Netfinity 3000 systems pre-installed with Windows NT 4.0 and using the integrated S3 Trio 3D AGP video adapter.
The COM port error condition is only seen when 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 errors, the following steps are suggested for Windows 95, Windows 98, and Windows NT 4.0.
Under Windows 95 or Windows 98, disable "Show window contents while dragging" under "Plus!" settings via the following steps:
1. Right click on the Windows 95 or Windows 98 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 Windows 95 or Windows 98, reduce video hardware acceleration rate under the Video Performance tab via the following steps:
1. Right click on the Windows 95 or Windows 98 desktop, then click on Properties.
2. Click on the Settings tab.
3. Depending on the installed version of Windows 95 or Windows 98, 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 Windows NT 4.0, perform the following steps:
1. Using the steps outlined above, disable "Show window contents while dragging."
2. Verify "FIFO Enabled" is checked under COM port settings via the following steps:
a. Click on Start, Settings, and Control Panel.
b. Double click on the Ports icon and highlight the appropriate COM port. Click on Settings.
c. Click on Advanced and verify that "FIFO Enabled" is checked.
For Windows 95, Windows 98 and Windows NT 4.0:
For customers using the HyperTerminal communications application included in Windows 95 Windows 98, and Windows NT it is recommended that they download the updated "HyperTerminal Private Edition" directly from the Hilgraeve Internet web site at the following URL: http://www.hilgraeve.com
Windows 95, Windows 98, and Windows NT are trademarks of Microsoft Corporation.
HyperTerminal is a trademark of Hilgraeve Inc.
SAS KEYWORDS:
PSY2 PSY2ERR PSY2COMM PSY2ADPT
CDT CDTCOMM CDTOEM CDTERR
CDTADPT D/T6862 D/T6892 6862
6892 UNCLASSIFIED CMVC84967 CMVC84966
CMVC84966F_1 NETFINITY 3000 D/T8476 CMVC8476
CMVC84967F_1 CMVC84966F_2 D/T6275 D/T6285
CMVC99768 CMVC99766
Search 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 | |
Hint Category |
Communications, Retain | |
Date Created |
04-05-98 | |
Last Updated |
08-09-98 | |
Revision Date |
05-09-99 | |
Brand |
IBM PC, IBM PC Server | |
Product Family |
PC 300PL, Netfinity 3000 | |
Machine Type |
6862, 6892, 8476 | |
Model |
all | |
TypeModel |
| |
Retain Tip (if applicable) |
H163570 | |
Reverse Doclinks |
USA=A, EMA=A, AFE=A, Date last altered: A98/05/07, Owning B.U.: USA |