Information Technology Reference
In-Depth Information
Place the pairs in the order of the pins they will be terminated on (1-2, 3-6, 4-
5, and 7-8). The color of the first two pairs depends on whether you use T568A or
T568B. Flatten the cable jacket at the end, to place the pairs side by side. Untwist
the pairs back to the jacket, placing the wires of each pair in the proper order,
according to the color code, as shown in Fig. 9.4. Arrange the wires so that they are
parallel and lay flat. Cross the wire for pin 6 over the pin 4 and 5 wires such that
the crossover is no more than 4 mm (0.16 in) from the edge of the jacket. Trim the
conductors to approximately 14 mm (0.55 in) from the edge of the jacket. Place the
plug over the conductors so that they extend all the way to the bottom of the termi-
nation slot and the jacket extends at least 6 mm (0.24 in) inside the plug body.
Crimp the plug using a modular crimp tool. After both ends of the cable have been
terminated, test the connections for continuity and proper conductor placement.
A crimp tool with a machined crimping die should be used for the best connec-
tions. A typical crimp tool is shown in Fig. 9.5. A proper crimp tool will cost as much
as $100 to $200, but will be well worth the expense. The tool should have a ratchet
action that will not allow the jaws to open until the plug has been fully crimped.
Inexpensive tool designs that were adequate for the smaller 6-pin modular telephone
connectors will typically fail to properly crimp the inside pins (pins 3, 4, 5, and 6)
when the design is extended to 8-pin widths. This may or may not cause immediate
failure of the connection, but you will have problems over time, even if the connec-
tion initially tests good. You can inspect a plug to see if it is properly crimped by
FIGURE 9.5
Typical crimp tool for modular connectors.
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