Data cable for a typical office is installed as a structured cabling system. With structured cabling, the network adapter port in each computer is connected to a wall port using a flexible patch cord. Behind the wall port, permanent cable is run through the wall and ceiling to an equipment room and connected to a patch panel. The port on the patch panel is then connected to a port on an Ethernet switch.

A structured cabling system uses two types of cable termination:

• Patch cords are terminated using RJ45 plugs crimped to the end of the cable.
• Permanent cable is terminated to wall ports and patch panels using insulation displacement connectors (IDC), also referred to as “punchdown blocks.”

The 100 m distance limitation is for the whole link, referred to as “channel link.” Each patch cord can only be up to 5 m long. Permanent link uses solid cable with thicker wires. Patch cords use stranded cable with thinner wires that are more flexible but also suffer more from attenuation.

Installing cable in this type of system involves the use of cable strippers, punchdown tools, and crimpers.

Cable Stripper and Snips

To terminate cable, a small section of outer jacket must be removed to expose the wire pairs. This must be done without damaging the insulation on the inner wire pairs. A cable stripper is designed to score the outer jacket just enough to allow it to be removed. Set the stripper to the correct diameter, and then place the cable in the stripper and rotate the tool once or twice. The score cut in the insulation should now allow you to remove the section of jacket.

Most Cat 6 and all Cat 6A cable has a plastic star filler running through it that keeps the pairs separated. You need to use electrician’s scissors (snips) to cut off the end of this before terminating the cable. There will also be a nylon thread called a “ripcord.” This can be pulled down the jacket to open it up more if you damaged any of the wire pairs initially. Snip any excess ripcord before terminating the cable.

Punchdown Tool

A punchdown tool is used to fix each conductor into an IDC. First, untwist the wire pairs, and lay them in the color-coded terminals in the IDC in the appropriate termination order (T568A or T568B). To reduce the risk of interference, no more than ½” (13 mm) should be untwisted. Use the punchdown tool to press each wire into the terminal. Blades in the terminal cut through the insulation to make an electrical contact with the wire.

Crimper

A crimper is used to fix a jack to a patch cord. Orient the RJ45 plug so that the tab latch is underneath. Pin 1 is the first pin on the left. Arrange the wire pairs in the appropriate order (T568A or T568B), and then push them into the RJ45 plug. Place the plug in the crimper tool, close it tightly to pierce the wire insulation at the pins, and seal the jack to the outer cable jacket.