Crimping the twisted pair Cables

 

 

1. Pull the cable off the reel to the desired length and cut (see below figure).

 

 

2. Stripe one end of the cable with the stripper.  This is about right to strip a little over 1/2" of the cover off the cable.  Turn the stripper about one turn or so.   Once scored, you should be able to twist the end of the jacket loose and pull it off with one hand while holding the rest of the cable with the other. 

 

 

3. Examine the wires for nicks. Cut off the end and start over if we see any.  We may have to adjust the blade with the screw at the front stripper.  Cable diameters and jacket thicknesses vary.

 

4. Spread and arrange the pairs roughly in the order of the desired cable end

 

 

5. Untwist the pairs and arrange the wires in the order of the desired cable end.  Flatten the end between thumb and forefinger. Trim the ends of the wires so they are even with one another.  It is very important that the untwisted end be slightly less than 1/2" long.

If it is longer than 1/2" it will be out-of-spec and susceptible to crosstalk.  If it less than slightly less than 1/2" it will not be properly clinched when RJ-45 plug is crimped on.  Flatten again.  There should be little or no space between the wires.

 

 

6. Hold the RJ-45 plug with the clip facing down or away from you.  Push the wire firmly into the plug. Looking through the bottom of the plug, the wire on the far left side will have a white background.  The wires should alternate light and dark from left to right.  The furthest right wire is brown.  The wires should all end evenly at the front of the plug. 

 

7. Hold the wire near the RJ-45 plug with the clip down and firmly push it into the left side of the front of the crimper.  Hold the wire in place squeeze the crimper handles quite firmly.  The crimper pushes two plungers down on the RJ-45 plug.  One forces what amounts to a cleverly designed plastic plug/wedge onto the cable jacket and very firmly clinches it.  The other seats the "pins," each with two teeth at its end, through the insulation and into the conductors of their respective wires.

 

 

8. Test the crimp. If done properly an average person will not be able to pull the plug off the cable with the bare hands.

 

9. Prepare the other end of the cable so it has the desired end and crimp.

 

10. If both ends of the cable are within reach, hold them next to each other and with RJ-45 clips facing away. If the plugs are wired correctly, and they are identical, it is a straight-thru cable.  If they are wired correctly and they are different, it is a crossover cable.

 

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