Cabletron T20xx Adapter Does Not Work After Installing SP2

After installing Service Pack 2, the Cabletron T20xx Token Ring network adapter in your computer may no longer function properly.

Removing Service Pack 2 does not correct the issue.

To work around this problem, manually enter the hardware address for the network adapter in the secondary address field in the driver configuration screen.

To locate the hardware address for the network adapter, do the following:

1. Reboot the computer to MS-DOS either from the Boot.ini menu or using a bootable floppy disk.
2. Run the setup utility for the adapter, it will display the correct hardware address for the card. The number will start with 0000B8xxxxxx.

The serial number is located on the mounting bracket of the adapter, but has no direct translation to the hardware address.

The setup utility software is available from Cabletron's FTP site at the following URL: NOTE: The network adapter may work with incorrect or "dummy" numbers, but this may create other network problems.

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.