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.
This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. (April 2023) |
On original 10BASE5 (Thick) Ethernet equipment, the MAU was typically clamped to the Ethernet wire and multi-wire cable-connected to the computer via a DA-15 port, which was also what was present on the NIC. This AUI cable could be up to 50m/160ft long, but was typically much shorter. With later standards, thicknet vampire taps and N connectors gave way to BNC connectors (for thinnet coax cables) and 8P8C connectors (for twisted-pair cables). MAUs for these still connected to NICs via AUI cables, but soon the MAU ceased to be a separate adapter and was generally integrated into the network interface controller. Eventually the entire Ethernet controller was often integrated into a single integrated circuit ("chip") to reduce cost.
In most modern switched or hubbed Ethernet over twisted pair systems, neither the MAU nor the AUI interfaces exist (apart, perhaps as notional entities for the purposes of thinking about layering the interface), and the category 5 (CAT5) or better cable connects directly into an Ethernet socket on the host or router. For backwards compatibility with equipment which still had external AUI interfaces only, adapter-type MAUs with 10BASE2 or 10BASE-T connectors long remained available after the obsolescence of original vampire-tap MAUs, but even adapter-type MAUs have become very rare as of the 2020s.