Some users have experienced difficulty using the AppleTalk PC Card with
AT&T 6300 computers. The AppleTalk PC Card design group tested the card
extensively with the AT&T 6300, so the products do work together.
The AT&T 6300 has seven built-in expansion slots; two of these slots are
programmed to accept cards that take advantage of the 8086's 16-bit
addressing capabilities.
Make sure that the AppleTalk PC card is being used in one of the 8-bit
slots. You must also ensure that you have either IRQ 2,3, or 4 available
for use. (The IRQ addresses that are available will vary, depending on
what cards are already installed.)