LocalTalk is a networking technology built into all Macintoshes that have modem and/or printer serial ports, most LaserWriters, and some other Macintosh printers. It was designed to give Macintoshes access to network services, such as file sharing and printing. However, because it communicates at only 230.4 Kbps and is normally limited to the AppleTalk protocol, it has largely been superseded by Ethernet. Macintosh computers that come with a built-in USB port and all models currently being shipped do not support LocalTalk.

LocalTalk networks are normally built with a linear-bus topology. Though Apple sells its own LocalTalk cable, most LocalTalk networks use Farallon PhoneNET connectors, which are cheaper and support longer cable lengths.