Assembly Of A Category 6 Shielded Solid Or Stranded Rj45 Plug

Twisted pair cables such as CAT5, CAT5e, CAT6 and CAT6a cable are a low cost and easy installation alternative to traditional coax cables for transmitting KVM and AV signals. KVM (keyboard-video-mouse) extenders via CAT5 may be used to remove computers from harsh or sensitive environments, or to restrict physical access to the computer. Video extension products such as VGA, DVI, S-Video or HDTV  extenders via CAT5 are used to extend video displays. Each extender consists of two units - the local and remote unit, which are interconnected using a CAT5/5e/6 cable.

Prepare the cable

You will first need CAT6 shielded cable (solid or stranded for the purposes of this article) cut to the desired length. The cable can be terminated before or after installation, even if you have a long run to make. Using a cable tester from VPI (http://www.vpi.us/) the cable can be easily tested for continuity, crossed pairs and pinouts to make sure all connections have been made properly.

Next you will need to make sure you have the correct plugs to terminate the cable with. Different plugs are intended to different types of cable, whether you have solid or stranded connectors, flat or round cable, shielded or unshielded, and CAT5, 5e, 6, or 6a. Be sure to use a plug suitable for your cable.

For tools you need a CAT5 wire stripper, wire cutters, RJ45 crimp tool, and a CAT5 cable tester.

Terminate the cable

First, carefully strip the jacketing from the cable to expose 1" of the insulated wire conductors and shield. Don't cut too deeply or you will knick the shield and wire insulation underneath. If you just score the cable jacket and bend the wire in several directions to finish the break, the result will be a good problem-free cut.

Next, peel the foil shield insulation back onto the cable jacket and trim to within approximately 1/4" of the jacket edge. Wrap the drain wire such that it is located at the bottom (locking-tab side) of the cable. Do not remove any insulation from the conductors.

Trim the + shaped divider (an insulator core within some manufacturer's CAT6 cables, so this may or may not be present) that separates each of the twisted pair all the way back to the cut edge of the jacket.

Next, untwist the wires all the way to the jacket edge (but not beyond) and arrange them according to TIA/EIA 568A or 568B standards.

For CAT6 cable, the RJ45 plug includes a loading bar used to properly space the wires for insertion into the RJ45 plug. Flatten and insert the wires into the loading bar. The loading bar has openings in it, one for each conductor. The wires must be placed in the proper order for either the TIA/EIA 568A or 568B standard.

With the wires in the proper order, slide the loading bar (with the raised edge up) all the way onto the cable as far as possible. Then trim off the excess wires that extend from the loading bar.

Insert the prepared cable into the RJ45 plug such that the loading bar is fully inserted and the cable jacket extends inside the plug. The jacket and shield should extend at least 1/4" into the plug for proper strain relief and shield connection. Make sure the drain wire is positioned at the bottom of the connector as this is where it will see the greatest contact with the shield of the RJ45 plug.

Using the RJ45 crimp tool, crimp the assembled termination to make it permanent. Firmly squeeze the handles to set the contacts and secure the plug. Once crimped, the termination should be tight and very difficult to remove.

Test the cable

Use the CAT5 cable tester to check your work. The tester will indicate proper continuity (complete connection end-to-end), make sure the pairs have been matched up properly, and that the pinout is according to the selected wire standard. If an end is wired incorrectly, the tester will indicate which end is incorrect. Simply cut off the end and try again.

Be sure to see more articles about CAT5 cable termination available from VPI. Other types of cable require slightly different procedures, so not all of the details for the cable you want to terminate will be covered in this article.