Apple Attachment Unit Interface (AAUI) is a 14-position, 0.050-inch-spaced ribbon contact connector. Early Power Macintosh and Quadras had an AAUI (Apple Attachment Unit Interface) port (rectangular shaped) for Ethernet, which requires a transceiver. To use twisted pair cabling, you would need to get a twisted pair transceiver for the computer with an AAUI port. Some Power Macintosh computers had both an AAUI and RJ-45 port; you can use one or the other, but not both.

The pin-out is:

 Pin   Signal Name     Signal Description
 ----  --------------  ---------------------------------
 1     FN Pwr          Power (+12V @ 2.1W or +5V @ 1.9W)
 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
AAUI signals have the same description, function, and electrical requirements as the AUI signals of the same name, as detailed in IEEE 802.3-1990 CSMA/CD Standard, section 7.

See also:

This article (or an earlier version of it) contains material from FOLDOC, used with permission.