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Attachment Unit Interface

 
Attachment Unit Interface

 
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Attachment Unit Interface
 
 
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An Attachment Unit Interface (AUI) is a 15 pin connection that provides a path between a node's Ethernet
Ethernet

Ethernet is a family of Data frame-based computer networking technologies for local area networks . The name comes from the physical concept of the Luminiferous aether....
 interface and the Medium Attachment Unit
Medium Attachment Unit

File:Transceiver .jpegMAU is an acronym for Medium Attachment Unit, also known as "transceiver", which converts signals on an Ethernet cable to and from Attachment Unit Interface signals....
 (MAU), sometimes known as a transceiver
Transceiver

A transceiver is a device that has both a transmitter and a receiver which are combined and share common circuitry or a single housing. If no circuitry is common between transmit and receive functions, the device is a transmitter-receiver....
. It is the part of the IEEE
Institute of Electrical and Electronics Engineers

The Institute of Electrical and Electronics Engineers or IEEE is an international non-profit, professional body for the advancement of technology related to electricity....
 Ethernet standard located between the Media Access Control
Media Access Control

The Media Access Control protocol sub-layer, also known as the Medium Access Control, is a sublayer of the Data Link Layer specified in the seven-layer OSI model ....
 (MAC), and the MAU.






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Aui Connectors
An Attachment Unit Interface (AUI) is a 15 pin connection that provides a path between a node's Ethernet
Ethernet

Ethernet is a family of Data frame-based computer networking technologies for local area networks . The name comes from the physical concept of the Luminiferous aether....
 interface and the Medium Attachment Unit
Medium Attachment Unit

File:Transceiver .jpegMAU is an acronym for Medium Attachment Unit, also known as "transceiver", which converts signals on an Ethernet cable to and from Attachment Unit Interface signals....
 (MAU), sometimes known as a transceiver
Transceiver

A transceiver is a device that has both a transmitter and a receiver which are combined and share common circuitry or a single housing. If no circuitry is common between transmit and receive functions, the device is a transmitter-receiver....
. It is the part of the IEEE
Institute of Electrical and Electronics Engineers

The Institute of Electrical and Electronics Engineers or IEEE is an international non-profit, professional body for the advancement of technology related to electricity....
 Ethernet standard located between the Media Access Control
Media Access Control

The Media Access Control protocol sub-layer, also known as the Medium Access Control, is a sublayer of the Data Link Layer specified in the seven-layer OSI model ....
 (MAC), and the MAU. An AUI cable may be up to 50 metres long, although frequently the cable is omitted altogether and the MAU and MAC are directly attached to one another.

An AUI connector is a DA-15 (D-subminiature
D-subminiature

The D-subminiature or D-sub is a common type of electrical connector used particularly in computers. Calling them "subminiature" was appropriate when they were first introduced, but today they are among the largest common connectors used in computers....
). It has a sliding clip in place of the thumbscrews normally found on a D-connector to hold two connectors together. This clip permits the MAU and MAC to be directly attached to one another even when their size and shape would preclude the use of thumbscrews. This clip is however frequently found to be awkward and/or unreliable.

AUI connectors became rarer beginning in the early 1990s. This was because it became more common for computers and hubs to incorporate the MAU, particularly as the 10BASE-T
10BASE-T

Ethernet over twisted pair refers to the use of a pair of copper cables, twisted around each other, for the physical layer of an Ethernet network ....
 standard became more common and use of 10BASE-5 (thicknet) and 10BASE-2 (thinnet) declined. The electrical AUI connection was still present inside the equipment. By the mid-1990s AUI had all but disappeared as fast Ethernet
Fast Ethernet

In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s, against the original Ethernet speed of 10 Mbit/s....
 became more common (fast Ethernet has an equivalent known as MII
Media Independent Interface

The Media Independent Interface is a standard interface used to connect a Fast Ethernet Media Access Control-block to a PHY. The MII may connect to an external transceiver device via a pluggable connector or simply connect two chips on the same printed circuit board....
). Gigabit Ethernet and 10 gigabit Ethernet have respectively the GBIC
GBIC

A gigabit interface converter is a standard for transceivers, commonly used with Gigabit Ethernet and fibre channel. By offering a standard, hot swappable electrical interface, one gigabit ethernet port can support a wide range of physical media, from copper to long-wave single-mode optical fiber, at lengths of hundreds of kilometers....
 and XAUI
XAUI

XAUI is a standard for extending the XGMII between the Media_Access_Control and PHY layer of 10 Gigabit Ethernet . XAUI is pronounced "zowie", a concatenation of the Roman numeral X, meaning ten, and the initials of "Attachment Unit Interface"....
 standards which are equivalent to AUI.

A modified form using a smaller connector called the AAUI
Apple Attachment Unit Interface

Apple Attachment Unit Interface is a mechanical re-design by Apple Inc. of the standard Attachment Unit Interface used to connect Ethernet transceivers to computer equipment....
 was used on Apple Macintosh computers in the early 1990s.

The pinout of the AUI is as follows:
Pin Circuit Description
3 DO-A Data Out Circuit A
10 DO-B Data Out Circuit B
11 DO-S Data Out Circuit Shield (not used)
5 DI-A Data In Circuit A
12 DI-B Data In Circuit B
4 DI-S Data In Circuit Shield
7 CO-A Control Out Circuit A (not used)
15 CO-B Control Out Circuit B (not used)
8 CO-S Control Out Circuit Shield (not used)
2 CI-A Control In Circuit A
9 CI-B Control In Circuit B
1 CI-S Control In Circuit Shield
6 VC Voltage Common
13 VP Voltage Plus (+12V)
14 VS Voltage Shield (not used)
Shell PG Protective Ground


See also

  • Thicknet
    10BASE5

    10BASE5 is the original "full spec" variant of Ethernet cable, using special cable similar to RG-8/U coaxial cable. This is a stiff, diameter cable with an impedance of 50 Ohm s , a solid center conductor, a foam insulating filler, a shielding braid, and an outer jacket....
  • Apple Attachment Unit Interface
    Apple Attachment Unit Interface

    Apple Attachment Unit Interface is a mechanical re-design by Apple Inc. of the standard Attachment Unit Interface used to connect Ethernet transceivers to computer equipment....
  • XAUI
    XAUI

    XAUI is a standard for extending the XGMII between the Media_Access_Control and PHY layer of 10 Gigabit Ethernet . XAUI is pronounced "zowie", a concatenation of the Roman numeral X, meaning ten, and the initials of "Attachment Unit Interface"....