Posted on October 9, 2020 - 3 minute read

How to make a network cable

The aim of this tutorial is to give an overview of cable networking theory and to show how to crimp a connector onto the end of a network cable.

DISCLAIMER: This tutorial focus only on copper-wired, twisted pair cables.

Requirements

The tools needed to make a network cable are:

Cables

Cat5 Cat6 cables

Ethernet cables consist of 8 copper wires, twisted in 4 pairs. The purpose of the twisting is to reduce electromagnetic radiation from the pair and crosstalk between neighboring pairs. This also improves rejection of external electromagnetic interference.

Twisted pair cables can be unshielded (UTP) or shielded (STP) with an additional layer of conductive material to attenuate electromagnetic waves external to the shield.

Some examples:

The contents of the cable are exactly the same no matter what the plastic jacket color is.

Connectors

The conventional name for the connectors on the ends of Ethernet cables is RJ-45. They consist of 8 pins, one for each wire inside an Ethernet cable.

RJ45 connectors

Colors and Pins

There is a sequence for the pins in an RJ-45 connector:

RJ45 pins

The important factor to remember when wiring RJ-45 plugs is the function of each pin.:

  1. Transmit positive signal (Tx+)
  2. Transmit negative signal (Tx-)
  3. Receive positive signal (Rx+)
  4. Nothing
  5. Nothing
  6. Receive negative signal (Rx-)
  7. Nothing
  8. Nothing

Following that sequence, there are two main standard pinouts (or orders) for the colored wires of the cable.

568A RJ-45 TIA-568A pinout:

  1. Green stripe
  2. Green solid
  3. Orange stripe
  4. Blue solid
  5. Blue stripe
  6. Orange solid
  7. Brown stripe
  8. Brown solid

568B RJ-45 TIA-568B pinout:

  1. Orange stripe
  2. Orange solid
  3. Green stripe
  4. Blue solid
  5. Blue stripe
  6. Green solid
  7. Brown stripe
  8. Brown solid

pin standards

It doesn’t matter which of these standards you use just as long as you are consistent when crimping connectors onto both ends of a cable.

Straight, crossover or rollover?

The distinction between a straight through, crossover, and rollover cable comes down to the way that the connectors on each end are wired.

Making your cable

Check out my video about crossover cables for some visuals.

  1. Using a cable stripper, a knife or a pair of scissors, cut the outter plastic jacket of the Ethernet cable. CAUTION: be gentle! If you go too deep you will cut through the inner wires, exposing the copper.
  2. Untwist the pairs and straight them to make them easier to manipulate.
  3. Arrange them in the desired standard.
  4. Measure the wires to the be enough to fit into the RJ-45 connector.
  5. Cut off the excess wire. Ensure to level the wires, they should align to the flat edge of the connector.
  6. Carefully, slide the wires inside the connector. Push them enough to see the copper at the edge of the connector.
  7. Crimp it. The pins should pierce throught the wires.
  8. Repeat the process on the other end of the cable.
  9. Test the cable using a cable tester. Plug each connector into the tester and turn it on. All pins should send and receive signal. If any pins do not light up on the tester, the connector was badly crimped. Cut the damaged connector and start over.

Conclusion

In this tutorial, you learned the basics of cable networking theory and how to crimp your own network cable.