VDV Works Virtual Hands-On Training


Cat 3 and Cat 5/5E/6 UTP Termination

110 Punchdown block - Part 2


Step 2 NEXT BACK  Examining and Preparing The Cables

You will need: 2 Cat 5 UTP cable lengths, cable stripper. Here's one of the simple, but effective jacket strippers cable manufacturers give away.


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Let's begin the process by stripping about 2 inches (50 mm) off the incoming cable jacket to expose the 4 pairs of wires. Use a jacket cutter to cut the jacket without damaging the individual wire strands - it's best to cut almost through then twist the cable to break it. Then pull the jacket off.

There are many types of jacket strippers on the market, from simple (and usually free from manufacturers of cable) to complex, like the one shown above. The major concern with removing the jacket is to not cut the insulation on the wires, as that may adversely affect the performance of the cable.

Some installers take off about 2 inches (50 mm) of jacket and use the ripcord to remove the jacket another 2-3 inches (50-75 mm) to insure no damage has been done to the wires.









Notice the twists in the pairs of wires. These twists are critical to the Cat 5 performance. They must be maintained to within 1/2 inch (12 mm) of the termination point.

Note the different twist rates of the pairs. The different twist rates help minimize crosstalk, since each pair is an antenna tuned to a different frequency.

Also be aware of the 4 color coded pairs: blue, orange, green, and brown. Each pair consists of the solid color wire and a wire with white and a stripe of color.

The convention is to remember to order them in this way: BL-O-G, which is BLue, Orange, Green, and Brown by default. It is also standard to terminate the white striped wire of the pair first, as in: first, white-blue; second, blue; third, white-orange; fourth, orange; etc.


Separate the twisted pairs to access the individual wires, but leave 1/2 inch (12 mm) of twists exposed beyond the end of the jacket.The easiest way to undo the twists is to use a small flat bladed screwdriver as a wedge to pry them apart. You do not have to strip the individual wires. The contacts will be made by punchdowns piercing the jackets and establishing contact.




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