PhoneNet, developed by Farallon Computing (now known as Netopia), is an implementation of the AppleTalk physical layer. It made use of standard unshielded twisted-pair telephone wire, in the form of four-conductor patch cords, with 6 position modular connectors (same as used in the popular RJ11 telephone connectors).

These modulators were connected to a PhoneNet transceiver. PhoneNet networks are usually arranged with cables connecting to transceivers in a daisy-chain topology.

PhoneNet was developed as an improvement on LocalTalk, the commonly-used implementation of the AppleTalk physical layer at the time, which used shielded twisted-pair cabling.

PhoneNet-wired networks were more favorable in comparison to LocalTalk-wired networks since networks using PhoneNet were less expensive, due to the use of unshielded twisted-pair cabling unlike LocalTalk, which uses the more expensive shielded twisted-pair cabling.

It was also more reliable than LocalTalk, since the connections in a PhoneNet-wired network do not accidentally disconnect as easily. PhoneNet is capable of travel on many pre-existing phone cables and phone jacks where just the inner pair was utilized for RJ-11 telephone service, since PhoneNet made use of the "outer" pair of the modular connector.

Through PhoneNet, entire floors of computers achieved easy networking due to the ability of PhoneNet to make use of an existing phone wire in an office. Construction of star topology networks of up to 48 devices was made easy with the introduction of a 12-port hub by Farallon Computing.

To create such a network, all that needed to be done was add jacks at the work stations and add jumpers in the phone closet. With all of the advantages of PhoneNet over LocalTalk wiring, it became the more commonly-used system in low-cost networking.

Both LocalTalk and PhoneNet were superseded in the early 1990’s with the inception of Ethernet-based networking, which became universal on the personal computer and was installed by most offices.

In 1998, iMac was released and new Macintosh models no longer featured the traditional RS-422 Mac serial port, rendering both LocalTalk and PhoneNet obsolete. Currently, Ethernet, Wi-Fi or (less commonly) IP-over-FireWire is used for most Macintosh networking.