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Service Hints & Tips

Document ID: YAST-3JJQTC

ISDN External Modem - Fails to connect at high speeds

Applicable to: World-Wide

Symptom:
IBM PC300/700 Series 65x7, 68x7, 6589, and 6899 IntelliStation Z-Pro, PCServer 310 (8639-oEx) and PCServer 315 (8638-PSx/PJx,KJx,KSx) systems with ISDN external modems connected via the serial ports may fail to connect at speeds of 128kbps and higher.

Problem Isolation Aids:
The condition is most noticeable when attempting to transmit via two channels (B1 and B2) to achieve a transmission rate of 128kbps. The COM port speed will be set to 115.2kbps through the communication software (e.g. Dial-Up Networking for Windows95).

Solution:
This is not a defect. DO NOT replace system hardware.

The systems mentioned above meet all design specifications and operating performance requirements. This condition is a design characteristic of the serial transceiver chip used in the above PC 300 & 700 and PCServer 310/315 Series systems.

If you require high speed ISDN communications (e.g. 128kbps), either of the following recommendations should be considered:

1. Use an internal ISDN modem.
2. Acquire a serial adapter card designed to accommodate high ISDN transmission speeds.

Note: Each recommendation has been tested and is supported for high speed ISDN communication rates in the PC 300/700 and PCServer 310/315 Series systems.

Search Keywords

Hint Category

Performance

Date Created

30-06-97

Last Updated

01-12-98

Revision Date

19-11-99

Brand

IBM Options

Product Family

Modems

Machine Type

128K

Model

TypeModel

Retain Tip (if applicable)

H16219

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