LocalTalk
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LocalTalk is a particular implementation of the physical layer of the AppleTalk networking system from Apple Computer. LocalTalk specifies a system of four-wire cabling, plugged into self-terminating transceivers, running the AppleTalk protocol stack, at a rate of 232 kbit/s.
Networking was envisioned in the Macintosh during planning, so the Mac was given expensive multi-mode (RS-232/RS-422) capable serial ports. Originally released as "AppleTalk Personal Network", LocalTalk used shielded twisted-pair cable with 3-pin Mini-DIN connectors. Cables were daisy-chained from transceiver to transceiver. Each transceiver had two 3-pin Mini-DIN ports, and a cable to connect to the Mac's DB-9 serial connector. Later, when the Mac Plus introduced the 8-pin Mini-DIN serial connector, transceivers were updated as well.
As time passed, LocalTalk was surpassed in performance, reliability and convenience.
- Other network technologies such as token ring and Ethernet via 10BASE-T (and, later, 100BASE-T) offered higher performance. AppleTalk could run over these transports. Early models of Power Macintosh and the Macintosh Quadra supported 10-BASET via the Apple Attachment Unit Interface while still supporting LocalTalk-based networking. Users could pick what kind of connection to use via a control panel. The improved performance led to LocalTalk being less frequently used in office situations where performance mattered.
- A variation of LocalTalk, called PhoneNet, was introduced by Farallon Computing. It used standard telephone wire with RJ-11 connectors connected to a PhoneNet transceiver, instead of the expensive shielded twisted-pair cable. In addition to being lower cost, PhoneNet-wired networks were more reliable due to the connections being more difficult to accidentally disconnect. The improved reliability and lower cost led to PhoneNet largely supplanting LocalTalk wiring in low cost networking.
- The decreasing cost of ethernet hubs offered much of the convenience of LocalTalk. Much later (long after the LocalTalk was dropped from the Macintosh), wireless standards such as 802.11b offered higher convenience in adhoc networking.
With the release of the iMac in 1998 the traditional Mac serial port disappeared — and thus, the ability to use both LocalTalk and PhoneNet — from new models of Macintosh. LocalTalk-to-Ethernet bridges were introduced to allow legacy devices (especially laser printers) to function on newer networks. For very old Macintosh computers, LocalTalk remains the only option.
See also
- LocalTalk is not to be confused with LonTalk , although both run over twisted pair telephone cable.