Apple Mac Performa 5300CD - Manual (Page 126)

To use Ethernet, you need to change the network connection in the Network
control panel. (For instructions on how to select a network connection and
other information about using your Macintosh on a network, see the
“Networks & Telecommunications” topic of Macintosh Guide, available in
the Guide [h] menu.)
IMPORTANT Your Macintosh supports EtherTalk Phase 2 (AppleTalk Phase 2
Protocols for Ethernet networks) and TCP/IP (via MacTCP software). Your
Macintosh does not support EtherTalk Phase 1 (AppleTalk Phase 1 protocols
for Ethernet networks).
CAUTION The use of an Ethernet card will make your Macintosh a Class
A computing device, according to FCC regulations.
116 Appendix D