AT-FS232 and AT-FS232/x Series Installation Guide
9
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-FS232 and AT-FS232/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-FS232 or AT-FS232/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.
Fiber Optic Port
The AT-FS232 and AT-FS232/x Series Bridging Converters have one
100Base-FX fiber optic port. The fiber optic port features an SC connector.
Port Speed
The fiber optic port is compliant with the 100Base-FX standard and has a
fixed operating speed of 100 Mbps. The end-node connected to the fiber optic
port on the bridging converter must also be able to operate at 100 Mbps.
Duplex Mode
The fiber optic port on the bridging converter can operate in half- or full-
duplex mode. You must set the duplex mode manually using the DIP switches
on the back of the unit.
