This is an acronym for Apple Attachment Unit Interface. This was Apple's proprietary combination Eterhenet port that supported both 10Base-T and the 10Base-2. AAUI required a transceiver (one on each machine) and a crossover Ethernet cable.

AAUI

The pin-out configuration is shown below:

  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

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