Apple Attachment Unit Interface (AAUI) is a mechanical re-design by
Apple
An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...
of the standard
Attachment Unit Interface
The Attachment Unit Interface (AUI) is a physical and logical interface defined in the IEEE 802.3 standard (additionally published in FIPS PUB 107) for 10BASE5 Ethernet and the earlier DIX standard. The physical interface consists of a 15-pin D ...
(AUI) used to connect computer equipment to
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 ...
.
The AUI was popular in the era before the dominance of
10BASE-T
1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sp ...
networking that started in the early 1990s; the AAUI was an attempt to make the connector much smaller and more user friendly, though the proprietary nature of the interface was also criticized.
[
]
FriendlyNet
AAUI is part of a system of Ethernet peripherals intended to make connecting over Ethernet easier. At the time of the introduction of AAUI, Ethernet systems usually were 10BASE2
10BASE2 (also known as cheapernet, thin Ethernet, thinnet, and thinwire) is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network. During the mid to late 1980s, this was the dominant ...
, also known as thinnet. Apple's system is called FriendlyNet. A FriendlyNet 10BASE2 system does not use BNC T-connectors or separate terminators. Instead of a single BNC connector
The BNC connector is a miniature quick-connect/disconnect RF connector, radio-frequency connector for coaxial cable. It was introduced on military radio equipment in the 1940s, and has since become widely used in radio systems and as a common t ...
that is inserted into a T-connector placed inline, the FriendlyNet transceiver has two BNC connectors, one on each side, to which the cables are attached. The transceiver automatically terminates the network
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
Mathematics
...
if a cable is missing from either side. Additionally, Apple 10BASE2 cables terminate the network when no device is attached to them. Thus the number of mistakes that could be made hooking up a thinnet network is reduced considerably. Since any of these mistakes can disable the network segment, this presents a significant improvement.
FriendlyNet equipment was expensive. Because of this, Apple's computers, billed as having built-in Ethernet, were expensive to connect to Ethernet, perhaps adding as much as a tenth to the total price of the computer system. Additionally, AAUI held no advantage for any system other than 10BASE2, and thus as 10BASE-T became ubiquitous it became impossible to justify the cost of an external transceiver. Apple eventually abandoned the system and sold off the name.
Macintosh Quadra
The Macintosh Quadra is a family of personal computers designed, manufactured and sold by Apple Inc., Apple Computer, Inc. from October 1991 to October 1995. The Quadra, named for the Motorola 68040 central processing unit, replaced the Macintosh ...
, Centris
The genus ''Centris'' contains circa 250 species of large apid bees occurring in the Neotropical and Nearctic realms, from Kansas to Argentina. Most females of these bees possess adaptations for carrying floral oils rather than (or in additi ...
, PowerBook 500
The PowerBook 500 series (codenamed ''Blackbird'', which it shared with the older Macintosh IIfx) is a range of Apple Macintosh PowerBook portable computers first introduced by Apple Computer with the 540c model on May 16, 1994. It was the fir ...
, Duo Dock II (for PowerBook Duo) and early Power Macintosh
The Power Macintosh, later Power Mac, is a family of personal computers designed, manufactured, and sold by Apple Inc., Apple Computer, Inc as the core of the Mac (computer), Macintosh brand from March 1994 until August 2006.
Described by ''Mac ...
es have AAUI ports, which require external transceivers. By the time AAUI was nearing the end of its life, the cost of an AAUI transceiver became a burden for consumers. Later models include both AAUI and 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 ...
ports for directly connecting 10BASE-T; either can be used, but not both at the same time. AAUI connectors are also present on some Processor Direct Slot
A processor direct slot (PDS) is a slot incorporated into many older Macintosh models that allowed direct access to the signal pins of a CPU, similar to the functionality of a local bus in PCs. This would result in much higher speeds than having ...
Ethernet adapter cards used in Macintosh LC
The Macintosh LC is a personal computer designed, manufactured, and sold by Apple Computer, Inc. from October 1990 to March 1992.
Overview
The first in the Macintosh LC family, the LC was introduced with the Macintosh Classic (a repackaging ...
and Performa
The Macintosh Performa is a family of personal computers designed, manufactured and sold by Apple Computer, Inc. from 1992 to 1997. The Performa brand re-used models from Apple's Quadra, Centris, LC, Classic, and Power Macintosh families ...
machines. AAUI had disappeared by the late 1990s, when new Apple machines, starting with the beige Power Macintosh G3
The Power Macintosh G3 (also sold with additional software as the Macintosh Server G3) is a series of personal computers designed, manufactured, and sold by Apple Inc., Apple Computer from November 1997 to August 1999. It represented Apple's fi ...
series, include only the modular connector ports.
Third-party vendors
Many third parties also created AAUI transceivers. Most made simplifications to the connectors and cables, presumably to reduce costs. Most third parties, as well as any non-Apple equipment, would use standard 10BASE2 cabling, including T-connectors and manual termination. Additionally, Apple's 10BASE2 cables were not appropriate for all uses since they only came in fixed lengths and the ends were not detachable, making it difficult to wire them through walls. Unfortunately, when mixing and matching Apple and non-Apple 10BASE2 devices, there were many seemingly natural configurations of cables and connectors which would cause the network to become unreliable or unusable in the area, reducing the value of the complex and proprietary Apple 10BASE2 wiring system.
Connector and signals
AUI uses a DA-15 connector
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, ...
and a sliding clip to mechanically secure the connection. AAUI replaces these with a small 14-position, 0.05-inch-spaced ribbon contact connector. This connector may have been chosen to avoid confusion with the monitor port on early Macintosh
Mac is a brand of personal computers designed and marketed by Apple Inc., Apple since 1984. The name is short for Macintosh (its official name until 1999), a reference to the McIntosh (apple), McIntosh apple. The current product lineup inclu ...
es, which also uses a DA-15. The connector locks into position using two clips or hooks on the sides of the connector outside of the shell which automatically clicks on when plugged in, and can be removed by pulling back on a sliding sheath over the body of the connector, disengaging the hooks. Third-party AAUI devices often omit this sheath, requiring the user to directly squeeze small tabs on the sides of the plug housing to detach the hooks.
AAUI signals have the same description, function, and electrical requirements as the Attachment Unit Interface
The Attachment Unit Interface (AUI) is a physical and logical interface defined in the IEEE 802.3 standard (additionally published in FIPS PUB 107) for 10BASE5 Ethernet and the earlier DIX standard. The physical interface consists of a 15-pin D ...
(AUI) signals of the same name, as detailed in IEEE 802.3
IEEE 802.3 is a working group and a collection of standards defining the physical layer and data link layer's media access control (MAC) of wired Ethernet. The standards are produced by the working group of the Institute of Electrical and Electro ...
-1990 CSMA/CD Standard, section 7, with the exception that most hosts provide only 5 volts of power rather than the 12 volts required for most AUI transceivers. An adapter containing a power supply
A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, electric current, current, and frequency to power ...
to provide the required 12 volts was available from Apple to permit connection of standard AUI transceivers to an AAUI port. This facilitated direct connection to 10BASE-F
The early generation of Ethernet standards had a maximum throughput of . In 10BASE-X, the 10 represents its maximum throughput of , BASE indicates its use of baseband transmission, and X indicates the type of medium used. Classic Ethernet include ...
(fibre optic
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at ...
) and 10BASE5
10BASE5 (also known as thick Ethernet or thicknet) was the first commercially available variant of Ethernet. The technology was standardized in 1982 as IEEE 802.3. 10BASE5 uses a thick and stiff coaxial cable up to in length. Up to 100 stat ...
(ThickNet) Ethernet networks, for which AAUI transceivers were not available.
See also
References
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{{Ethernet
Apple Inc. peripherals
Macintosh peripherals
Ethernet
Computer connectors