Apple Attachment Unit Interface
From Free net encyclopedia
Image:Asante-aaui.jpg Image:AUI Connectors.jpgApple Attachment Unit Interface (AAUI) is a mechanical re-design 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 networking that started in the early 1990s; AAUI was an attempt to make the connector much smaller and more user friendly.
AUI used a full-sized 15-pin DIN connector that used a difficult-to-use sliding clip for mechanical connections (in place of even more-annoying thumbscrews). AAUI replaced these with a small 14-position, 0.050-inch-spaced ribbon contact connector. The connector was locked into position using two clips on the side of the connector which automatically clicked on when plugged in, and could be removed simply by squeezing small flanges on the side of the connector housing.
AAUI signals have the same description, function, and electrical requirements as the Attachment Unit Interface (AUI) signals of the same name, as detailed in IEEE 802.3-1990 CSMA/CD Standard, section 7, with the exception that most hosts provide only 5 volt power rather than the 12 volts required for most AUI transceivers. An adaptor containing a power supply 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 (fibre optic) and 10BASE5 (ThickNet) Ethernet networks, for which AAUI transceivers were not available.
Macintosh Quadra, Centris and early Power Macintoshes had an AAUI port, which requires an external transceiver. Generally the transceivers cost a significant percentage of the cost of a low-cost Ethernet card on the PC. Later models included both an AAUI and RJ-45 port for directly connecting 10BASE-T; you can use one or the other, but not both. AAUI connectors were also present on some Processor Direct Slot Ethernet adaptor cards used in Macintosh LC and Performa machines. AAUI had disappeared by the late 1990s, when all new machines included only 10BASE-T.
The pin-out is:
| Pin | Signal Name | Signal Description |
|---|---|---|
| 1 | FN Pwr | Power (+12 V @ 2.1 W or +5 V @ 1.9 W) |
| 2 | DI-A | Data In circuit A |
| 3 | DI-B | Data In circuit B |
| 4 | VCC | Voltage Common |
| 5 | CI-A | Control In circuit A |
| 6 | CI-B | Control In circuit B |
| 7 | +5V | +5 volts (from host) |
| 8 | +5V | Secondary +5 volts (from host) |
| 9 | DO-A | Data Out circuit A |
| 10 | DO-B | Data Out circuit B |
| 11 | VCC | Secondary Voltage Common |
| 12 | NC | Reserved |
| 13 | NC | Reserved |
| 14 | FN Pwr | Secondary +12V @ 2.1W or +5V @ 1.9W |
| Shell | Protective Gnd | Protective Ground |
See also
References
- This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL.