Each PC card has a small amount of nonvolatile memory. When pccardd detects a card, it reads that memory and tries to match it to an entry in pccard.conf . If every characteristic matches the driver, and the laptop has the proper resources free, the card will run. If the card doesn't run, chances are the entry is incorrect somewhere. The manufacturer and version appear on every PC card.
Some cards have one or two fields of additional information.
Pccardd uses the manufacturer, version, and other information to match a card to a configuration. The index entry indicates which of the card's possible configurations to use. The driver is the kernel driver this card uses. The interrupt is the IRQ the card takes. It's much better in the long run to get the irq line correct than to tweak individual entries.