Information Technology Reference
In-Depth Information
FIGURE 8.5
Connectorized patch panel.
for connections between the 50-pin connector and each jack is dependent on pair num-
bering. It is customary to connect the pair color codes in the order given in Chapter 5
for the wire pairs. In other words, pair 1 of a 25-pair (50-wire) cable connects to pins
1 and 26 on the connector, pair 2 connects to pins 2 and 27, etc. However, the connec-
tions do not go to a 25-pair cable, but lead instead to individual jacks, either four or
eight wires at a time. So, a 4-pair jack panel connection would have pairs 1 through 4
connected to the first jack, pairs 5 through 8 to the second jack, and so on, in turn, up
to the sixth jack (all that can be served by one 50-pin connector).
Then, at each modular jack, the pairs are connected in a pattern consistent with
either T568A or T568B. This distinction is important, as the two patterns reverse the
connections for pairs 2 and 3. Remember that T568B is equivalent to Lucent (AT&T)
258A and is probably what you will get if you don't specify. You should always spec-
ify the patch jacks and connectors to be mapped to T568B or T568A, whichever
matches your hub cord. You are still free to use a different pattern for the horizontal
cable and patch, since it is separate from the hub-to-patch connection.
Panels that use all eight pins of each jack are clearly identified as to pattern
mapping, but panels that use only four pins use a skeleton of one of the TIA pat-
