Hardware manual

Chapter 5 - Installing the CAB 4n
28 Version 1.6.0.0 March 15, 2010
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.
Link connections
CAB 4n, 8i, 8o and 16 series products feature built-in Buddy Link functionality for creating
backup I/O configurations in mission critical systems.
Each CAB 4n Series product features rear panel, dual BNC connectors labeled LINK IN and
LINK OUT. These connectors enable you to connect adjacent CAB units for redundancy and
define the role of dual units.