Medium-dependent interface
![Hub with three MDI-X ports and one switchable port circa 1998](/Images/godic/202501/26/4_port_netgear_ethernet_hub3656.jpg")
![Straight-through MDI to MDI-X connection for 10BASE-T](/Images/godic/202501/26/Ethernet_MDI_to_MDIX.svg3656.png")
![MDI to MDI connection with Ethernet crossover cable](/Images/godic/202501/26/Ethernet_MDI_crossover.svg3656.png")
A medium dependent interface (MDI) describes the interface (both physical and electrical) in a computer network from a physical layer implementation to the physical medium used to carry the transmission. Ethernet over twisted pair also defines a medium dependent interface crossover (MDI-X) interface. Auto MDI-X ports on newer network interfaces detect if the connection would require a crossover, and automatically chooses the MDI or MDI-X configuration to properly match the other end of the link.