PhoneNet was an implementation of the AppleTalk networking physical layer created by Farallon Computing (now Netopia). Instead of using expensive shielded twisted pair wiring as in Apple's LocalTalk implementation, PhoneNet uses standard four-conductor telephone patch cords and modular connectors. Like LocalTalk, the theoretical maximum speed for data transfer was 230 kbit/s, and it is generally used in a daisy chain topology.
Unlike LocalTalk's balanced and grounded implementation, PhoneNet used only two lines of the four in a typical cable. As normal telephone equipment also normally used only two lines, PhoneNet could be plugged into existing phone lines in some instances, allowing both phone calls and networking over a single cable. Generally this requires some hand-crimping of a cable using three RJ11 jacks, connecting a single jack to two, one with two wires for the phone and the other with the other two for networking.
Though PhoneNet transceivers are still available from third parties for use on legacy Macintosh networks, no current Mac model comes with the RS-422 serial ports that are required for PhoneNet transceivers; virtually all modern Macintosh networking is done using Ethernet or Wi-Fi.