The Apple Ethernet Twisted Pair Transceiver used the Apple Attachment Unit Interface (AAUI) to connect Ethernet transceivers to computers. This transceiver used a 10BASE-T connector. This version of the transceiver used an RJ45 port.
Apple computers with an AAUI port included Macintosh Quadra, Centris, PowerBook 500, Duo Dock II (for PowerBook Duo), early Power Macintosh computers, and some Macintosh LC and Performa computers.
When I first began as a Technology Coordinator for a school district, our Macintosh LC520 network was connected entirely using Apple Ethernet Twisted Pair Transceiver devices and BNC connectors in a daisy-chain setup. When we updated the computer lab, we stopped using the AAUI port and installed 10BASE-T cards in the computers.