Allied Telesis AT-FS238b/2 - Manual (Page 23)

AT-FS238a/x and AT-FS238b/x Series Installation Guide
13
Auto MDI/MDI-X
An RJ-45 twisted pair port on a 10 Mbps or 100 Mbps Ethernet network
device can have one of two possible wiring configurations: MDI or MDI-X. The
RJ-45 port on a PC, router, or bridge is typically wired as MDI, while the
twisted pair port on a bridging converter or hub is usually MDI-X.
When the twisted pair port on the AT-FS238a/x and AT-FS238b/x Series
converters is set to Auto-Negotiation, the port features automatic MDI/MDI-
X. The RJ-45 port automatically determines the configuration of the port on
the end-node and then configures itself appropriately. This features allows
you to use either a straight-through or crossover cable when connecting an
end-node to the twisted pair port.
When the port on the AT-FS238a/x or AT-FS238b/x Series converter is not set
to Auto-Negotiation, the port defaults to MDI-X. To connect to an end-node
that has the same wiring configuration, such as MDI-X to MDI-X, you would
use a crossover twisted pair cable. To connect to an end-node that has
different port wiring configuration, such as MDI to MDI-X, you would use a
straight-through cable.