Apple PC Serial and Parallel Card - Manual (Page 5)

Preparing the slots
7 Unscrew and remove the metal port access covers for the slots you need.
If you are installing the PC Serial and Parallel Card at the same time you are
installing a PC Compatibility Card, unscrew and remove the metal covers to
both PCI slots.
If you already have a PC Compatibility Card installed in your computer, then
unscrew and remove the card without disconnecting the audio cables. Refer to
your PC Compatibility Card user’s manual or
PC Compatibility Card Update
for information on how to remove the bracket that holds the PC Compatibility
Card in place.
Next, unscrew and remove the metal port access cover to the top (first) slot.
Keep the screws; you will reinsert them later.
First PCI slot
PC Compatibility
Card
Remove the screw that
holds the port cover in place.
Port access cover
5 Installing the Card in a Power Macintosh 4400 or 7220