Apple Macintosh Performa 5400 Series - Manual (Page 131)

Installing a communication card
This section contains instructions for installing an Ethernet or internal
modem card in the communication slot in your computer.
Note: Using a modem is not the same as being connected to a local area
network. If you have an internal modem and the appropriate software that
makes use of it, you already have access to online services. You do not need
an Ethernet card unless you need to connect your computer to other
computers in an Ethernet network. For more information about using an
Ethernet card to connect to an Ethernet network, see “Connecting to an
Ethernet Network” in Appendix D.
Some communication cards designed for other communication slots
are not compatible with your computer and cannot be installed in its
communication slot. You can tell by examining the placement of the notches
on the card. Use the following illustration as a guide if you’re not sure you
have the correct type of card for the slot.
Vertical plate
Compatible
Compatible
Notches
Logic board
(side view)
Communication slot
Communication card
Notches
Not compatible
Notches
130 Appendix B