Medium Attachment Unit

A Medium Attachment Unit (MAU) is a transceiver which converts signals on an Ethernet cable to and from Attachment Unit Interface (AUI) signals.

On original 10BASE5 (Thick) Ethernet, the MAU was typically clamped to the Ethernet cable. With later standards it was generally integrated into the network interface controller and eventually the entire Ethernet controller was often integrated into a single integrated circuit ("chip") to reduce cost.