AT-3624TR Connectivity
44
RJ45 Connectors
The AT-3624TR uses 24 RJ45 connectors. Figure 44 shows a sample RJ45
connector.
MDI/MDI-X Switch
The 24 10BASE-T RJ45 ports on the AT-3624TR are generally used for
network connections between a hub and a transceiver. Network
connections require a standard “straight-through” cable, meaning that a
pin at one end connects to a pin with the same number at the other end.
However, you may want to use one of these ports to link one hub to
another hub. This type of connection requires the signal to “crossover,” so
that the TX (transmit) pin at one end connects to the RX (receive) pin at
the other end. You can accomplish this in either of two ways:
❑
You can use a special cross-over cable, available commercially at
most electronic outlets.
❑
You can use a built-in MDI/MDI-X switch for internally crossing
the signal over, before it is transmitted through the cable.
ATI has incorporated an MDI/MDI-X switch into the AT-3624TR module
(see Figure 45). The Medium Dependent Interface (MDI/MDI-X) switch at
the upper left corner of the AT-3624TR front panel converts RJ45 Port 1
from a normal network connector into an internally crossed-over port for
hub-to-hub connection:
❑
The default setting for the switch is MDI-X (standard RJ45 port).
❑
If you want to use Port 1 to connect two hubs, you must set the
switch on one, and only one, of the hubs to the MDI position.
Figure 44:
RJ45 Connector
Pin 1
