PRB: Bus Speed 3C603 Token Link Card Problem w/ LAN Manager

ID Number: Q64793

2.00 2.10

OS/2

Summary:

SYMPTOMS

When attempting to start OS/2 or MS-DOS LAN Manager version 2.0 or

2.1 for the first time on a Gateway 2000 (25-MHz 386, 8 MB)

computer with a 3Com 3C603 Token Link card, NET STARTing the server

causes the OS/2 system to hang. At this point, only a power

shutdown can revive the system.

CAUSE

By default, a Gateway 2000 computer has a bus speed of 12 MHz,

which must be changed to 8 MHz by setting the appropriate jumpers

on the motherboard. Once the bus speed has been set to a lower

value (8 MHz), the 3C603 Token Link card will work correctly, and

so will OS/2 or DOS LAN Manager.

The reason the bus speed must be changed is that all ISA net cards

are designed to run with a bus clock of 6 to 8.333 MHz. Therefore,

a higher (or different) bus clock frequency will affect all ISA

devices in an unspecified manner.

EISA devices (net cards) are designed to handle higher bus clock

frequencies (up to 33 MHz).

Additional reference words: 2.00 2.01