User manual
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Crossover cables are used to connect switches to other switches or CABs directly to the DPU
card. Also, a crossover cable is what you would use if you were to connect a CAB to another
CAB, for use as a digital “snake”. A crossover cable is terminated the same way as a normal
cable, except that the TX and RX pins are "swapped" at one end to allow the transmit pair of
one device to connect to the receive pair of the other. Normally, this crossover action is done
within the switch, which is why you use a straight-through cable most of the time. It is very easy
to tell the difference between a crossover cable and a straight-through cable by looking at the
conductors in the RJ-45 connectors. If the wiring is identical at both ends, you are looking at a
straight-through cable. If it is different, you most likely have a crossover cable, or possibly, an
incorrectly terminated cable. Look carefully at the color of the conductors. It is important to note
that some switches include “uplink” ports. These ports are intended to serve as a connection to
another switch. As such, the uplink port is wired to use a straight-through cable instead of
requiring a crossover cable. On some switches, uplink ports share their connection with an
adjacent port, so be sure to read the manufacturer's instructions for proper use.