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LocalTalk is a particular implementation of the
physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer; The layer most closely associated with the physical connection between devices. This layer may be implemented by a PHY chip. The ...
of the
AppleTalk AppleTalk is a discontinued proprietary suite of networking protocols developed by Apple Computer for their Macintosh computers. AppleTalk includes a number of features that allow local area networks to be connected with no prior setup or the n ...
networking system from
Apple Computer Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company b ...
. LocalTalk specifies a system of shielded twisted pair cabling, plugged into self-terminating
transceiver In radio communication, a transceiver is an electronic device which is a combination of a radio ''trans''mitter and a re''ceiver'', hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. The ...
s, running at a rate of 230.4 kbit/s.
CSMA/CA Carrier-sense multiple access with collision avoidance (CSMA/CA) in computer networking, is a network multiple access method in which carrier sensing is used, but nodes attempt to avoid collisions by beginning transmission only after the channel i ...
was implemented as a random multiple access method. Networking was envisioned in the
Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc., Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and ...
during planning, so the Mac was given expensive
RS-422 RS-422, also known as TIA/EIA-422, is a technical standard originated by the Electronic Industries Alliance that specifies electrical characteristics of a digital signaling circuit. It was meant to be the foundation of a suite of standards that ...
capable
serial port In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. ...
s, first on a nine-pin D-connector, then on a Mini-DIN-8 connector. The ports were driven by the
Zilog SCC The SCC, short for Serial Communication Controller, is a family of serial port driver integrated circuits made by Zilog. The primary members of the family are the Z8030/Z8530, and the Z85233. Developed from the earlier Zilog SIO devices (Z8443), ...
, which could serve as either a standard
UART A universal asynchronous receiver-transmitter (UART ) is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. It sends data bits one by one, from the least significan ...
or handle the much more complicated
HDLC High-Level Data Link Control (HDLC) is a bit-oriented code-transparent synchronous data link layer protocol developed by the International Organization for Standardization (ISO). The standard for HDLC is ISO/IEC 13239:2002. HDLC provides both c ...
protocol, which was a packet oriented protocol that incorporated addressing, bit-stuffing, and packet checksumming in hardware. Coupled together with the RS422 electrical connections, this provided a reasonably high-speed data connection. The 230.4 kbit/s bit rate is the highest in the series of standard serial bit rates (110, 150, 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200, 230400) derived from the 3.6864 MHz clock after the customary divide-by-16. This clock frequency, 3.6864 MHz, was chosen (in part) to support the common asynchronous baud rates up to 38.4 kbit/s using the SCC's internal baud-rate generator. When the SCC's internal
PLL A phase-locked loop or phase lock loop (PLL) is a control system that generates an output Signal (electrical engineering), signal whose phase (waves), phase is related to the phase of an input signal. There are several different types; the simp ...
was used to lock to the clock embedded in the LocalTalk serial data stream (using its FM0 encoding method) a divide-by-16 setting on the PLL yielded the fastest rate available, namely 230.4 kbit/s. Originally released as "AppleTalk Personal Network," LocalTalk used shielded twisted-pair cable with 3-pin
Mini-DIN The mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN is similar to the larger, older DIN connector. Design Mini-DIN connectors are in diameter and come in seven patterns, wit ...
connectors. Cables were daisy-chained from transceiver to transceiver. Each transceiver had two 3-pin Mini-DIN ports, and a "pigtail" cable to connect to the Mac's
DE-9 The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems. Description, n ...
serial connector. Later, when the Mac Plus introduced the 8-pin Mini-DIN serial connector, transceivers were updated as well. A variation of LocalTalk called PhoneNet was introduced by
Farallon Computing Farallon, later renamed Netopia, was a computer networking company headquartered in Berkeley, and subsequently Emeryville, California, that produced a wide variety of products including bridges, repeaters and switches, and in their later Netopia inc ...
. It used standard unshielded side-by-side telephone wire, with six-position
modular connector A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets. Modular connectors were originally developed fo ...
s (same as the popular
RJ11 A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in the ...
telephone 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. In addition, because it used the "outer" pair of the modular connector, it could travel on many pre-existing phone cables and jacks where just the inner pair was in use for RJ11 telephone service. PhoneNet was also able to use an office's existing phone wire, allowing for entire floors of computers to be easily networked. Farallon introduced a 12-port hub, which made constructing star topology networks of up to 48 devices as easy as adding jacks at the workstations and some jumpers in the phone closet. These factors led to PhoneNet largely supplanting LocalTalk wiring in low-cost networking. The useful life of PhoneNet was extended with the introduction of LocalTalk switching technology by Tribe Computer Works. Introduced in 1990, the Tribe LocalSwitch was a 16 port packet switch designed to speed up overloaded PhoneNet networks. The widespread availability of
Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
-based networking in the early 1990s led to the swift disappearance of both LocalTalk and PhoneNet. They remained in use for some time in low-cost applications and applications where Ethernet was not available, but as Ethernet became universal on the PC most offices were installing it anyway. Early models of
Power Macintosh The Power Macintosh, later Power Mac, is a family of personal computers designed, manufactured, and sold by Apple Computer as the core of the Macintosh brand from March 1994 until August 2006. Described by ''MacWorld'' as "the most important te ...
and the
Macintosh Quadra The Macintosh Quadra is a family of personal computers designed, manufactured and sold by Apple Computer, Inc. from October 1991 to October 1995. The Quadra, named for the Motorola 68040 central processing unit, replaced the Macintosh II family as ...
supported 10BASE-T via the
Apple Attachment Unit Interface Apple Attachment Unit Interface (AAUI) is a mechanical re-design by Apple of the standard Attachment Unit Interface (AUI) used to connect Ethernet transceivers to computer equipment. AUI was popular in the era before the dominance of 10BASE-T ...
while still supporting LocalTalk-based networking. For older Macintosh computers that did not have built-in Ethernet expansion options, a high speed
SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interface ...
-to-Ethernet adapter was available, and was particularly popular on
PowerBook The PowerBook (known as Macintosh PowerBook before 1997) is a family of Macintosh laptop computers designed, manufactured and sold by Apple Computer from 1991 to 2006. During its lifetime, the PowerBook went through several major revisions and r ...
s. This enabled all but the earliest Macintosh models to access a high speed Ethernet network. With the release of the
iMac iMac is a family of all-in-one Mac desktop computers designed and built by Apple Inc. It has been the primary part of Apple's consumer desktop offerings since its debut in August 1998, and has evolved through seven distinct forms. In it ...
in 1998 the traditional Mac serial port — and thus, the ability to use both LocalTalk and PhoneNet — disappeared from new models of Macintosh. LocalTalk-to-Ethernet bridges were introduced to allow legacy devices (especially
printer Printer may refer to: Technology * Printer (publishing), a person or a company * Printer (computing), a hardware device * Optical printer for motion picture films People * Nariman Printer (fl. c. 1940), Indian journalist and activist * James ...
s) to function on newer networks. For very old Macintosh computers, LocalTalk remains the only option.


Design legacy

The LocalTalk connector had the distinction of being the first to use Apple's unified AppleTalk Connector Family design, created by Brad Bissell of
Frog Design frog (styled as ''"frog, part of Capgemini Invent"'') is a global creative and design consultancy founded in 1969 by industrial designer Hartmut Esslinger in Mutlangen, Germany, where it was initially named “esslinger design”. Soon after the ...
using
Rick Meadows Rick may refer to: People *Rick (given name), a list of people with the given name *Alan Rick (born 1976), Brazilian politician, journalist, pastor and television personality *Johannes Rick (1869–1946), Austrian-born Brazilian priest and mycol ...
' Apple Icon Family designs. LocalTalk connectors were first released in January 1985 to connect the
LaserWriter The LaserWriter is a laser printer with built-in PostScript interpreter sold by Apple, Inc. from 1985 to 1988. It was one of the first laser printers available to the mass market. In combination with WYSIWYG publishing software like PageMaker, ...
printer initially with the
Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc., Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and ...
family of computers as an integral part of the newly announced
Macintosh Office The Macintosh Office was an effort by Apple Computer to design an office-wide computing environment consisting of Macintosh computers, a local area networking system, a file server, and a networked laser printer. Apple announced Macintosh Offic ...
. However, well past the move to Ethernet, the connector's design continued to be used on all of Apple's peripherals and cable connectors as well as influencing the connectors used throughout the industry as a whole.


See also

*
AppleTalk AppleTalk is a discontinued proprietary suite of networking protocols developed by Apple Computer for their Macintosh computers. AppleTalk includes a number of features that allow local area networks to be connected with no prior setup or the n ...
*
Econet Econet was Acorn Computers's low-cost local area network system, intended for use by schools and small businesses. It was widely used in those areas, and was supported by a large number of different computer and server systems produced both by ...
*
List of device bandwidths This is a list of interface bit rates, is a measure of information transfer rates, or digital bandwidth capacity, at which digital interfaces in a computer or network can communicate over various kinds of buses and channels. The distinction can ...
{{DEFAULTSORT:Localtalk Apple Inc. hardware Network protocols Networking hardware Physical layer protocols Link protocols Legacy hardware