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 ...

networking Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematic ...

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 ...

. 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. Thes ...

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 ...

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 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, 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 signific ...

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 bot ...

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 whose phase is related to the phase of an input signal. There are several different types; the simplest is an electronic circuit consisting of a v ...

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, no ...

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 ...

. It used standard unshielded side-by-side telephone wire, with six-position modular connectors (same as the popular RJ11 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 1 ...

-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 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 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 In law, a legacy is something held and transferred to someone as their inheritance, as by will and testament. Personal effects, family property, marriage property or collective property gained by will of real property. Legacy or legacies may refer ...

(especially printers) 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' 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 PageMake ...

printer initially with the

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 Off ...

. 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.

Design legacy

See also