2001: When Apple introduced built-in ethernet, the port Apple standardized on wasn’t the regular “wide-phone-jack” connector used for 10Base-T ethernet on today’s systems. Instead, it was a proprietary new connector called AAUI, a combination port that supported both 10Base-T and the then-popular 10Base-2 Ethernet (a.k.a. Thin Net) – the catch was that you needed to buy a small adapter, called a transceiver, to use AAUI with either type of network.
Have an older Mac with AAUI and want to put it on your network? Or do you need a fast and easy way to transfer files from that older Mac to your new computer? 10Base-T transceivers are still easy to find for around $50, which is far less than a NuBus or PCI Ethernet card. (They may be available for even less on eBay.) The transceivers are true plug-and-play, too, since they just use the ethernet drivers built into the Mac OS.
Not sure which kind of port your computer has? Look on the back. Next to the ethernet symbol, which looks like this – <…> – you’ll either see a port that looks like a wide phone jack (10Base-T) or a small trapezoid-shaped connector with metal brackets on both sides (AAUI). A few systems from the mid-90s, like the Power Mac 8500, have both AAUI and 10Base-T connectors.
One issue: AAUI ports are designed to work solely in conjunction with transceivers, so there’s no such thing as an “AAUI cable”. If you wanted to share files between two AAUI-equipped Macs, you’ll need two transceivers and an ethernet crossover cable. In that case, file sharing over LocalTalk makes a much cheaper – if much slower – alternative.
short link: https://goo.gl/vKiiJ7