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While it's often easiest to buy your network cable ready to go, sometimes you need to make your own for a custom length or installation. Also called CAT 5 cable, CAT 6 cable, ethernet cable, or just the thing that connects your computer to the internet or a netwok -- any way you say it, even a beginner can make their own.

Steps:
1. Purchase a high quality crimping tool that fits RJ45 connectors. Also purchase more RJ45 connectors (cat 5/5e, cat 6) than you actually need, as inevitably some will have to be re-done.

2. Choose between CAT 5, CAT 5e, or CAT 6 cable. For almost any purpose other than the fastest and newest networks, CAT 5 will be fine.

3. Strip 1/2" to 3/4" of the outer shielding on the cable end, being sure not to cut the insulation of the stranded wires inside. A good quality crimping tool should make this easy, otherwise you can gently use a knife or wire cutters.

4. Untwist the twisted pair wires just enough to line them up properly, and no more. Once untwisted, do not re-twist the wires yourself. There is no need to strip the insulation from the individual wires.

5. Arrange the wires from left to right in this order: white with orange stripe, solid orange, white with green stripe, solid blue, white with blue stripe, solid green, white with brown stripe, solid brown.

6. Clip the ends of the wires such that they are all the same length.

7. Slide the wires into the RJ45 connector with the prong facing downward (away from you). Ensure the wires have lined up in the order you intended, and that they push all the way to the end of the plug.

8. Insert the plug in the crimping tool, and squeeze hard to crimp the plug.

9. Optionally, use a cable tester to confirm that your cable works correctly.


Tips:
You have made a patch cable, which is good for running from a switch or router to your PC. If you want to connect from a PC to a PC directly, you need to make a crossover cable, which has a different order of wires on one end. For crossover, do one end as stated above, and the other in this order: white with green stripe, solid green, white with orange stripe, solid blue, white with blue stripe, solide orange, white with brown stripe, solid brown.

For most purposed you should use cables of no more than 100 meters (approximately 300 feet) in length.

For most purposes it is better to use a switch or a router than a hub. A switch or router acts as a signal booster, while a hub does not.

Some modern switches and routers automatically detect whether the cable is a patch or crossover and adjust automatically, allowing you to use either. If your switch or router has a port called uplink, they have made that port specifically for you to use a patch cable when your really need a crossover, and the device will adjust automatically for you.

COLOR-CODE STANDARDS
Last updated: 8/9/2004

RJ45 network cables come in two types: straight-thru cables are used to connect a PC to a router or a hub, and crossover (or cross-wired) are used to connect two devices with identical interfaces (ie: computer to computer or hub to hub). In the following diagrams, devices transmit on TX pins, and receive on RX pins. Note that on the crossover cable the TX pins are connected to the corresponding RX pins, plus to plus and minus to minus.

There are two wire color-code standards: EIA/TIA 568A and EIA/TIA 568B. The codes are commonly depicted with RJ-45 jacks as follows (the view is from the front of the jacks):

Note that pins 4, 5, 7, and 8 are not used in either standard, and are not used or required to implement 100BASE-TX duplexing.

The actual cables are not physically that simple.  In the above diagram the right ends have been set up to match RJ45 jacks while the left ends have not. Also, the orange wires are not adjacent and the blue pair is upside-down. If we twist the wires into their appropriate pairs and set up both ends so that they form a 568A straight-thru cable and add a 180° twist, we get the following:

You must use a pair of twisted wires to connect a set of transmitter pins to their corresponding receiver pins.  You cannot use a wire from one pair and another wire from a different pair.

Keeping the above in mind, we can simplify the diagram for a 568A straight-thru cable by untwisting  the wires, except the 180° twist in the entire cable, and bending the ends upward.  Likewise, if we exchange the green and orange pairs in the 568A diagram we will get a simplified diagram for a 568B straight-thru cable.  If we cross the green and orange pairs in the 568A diagram we will arrive at a simplified diagram for a crossover cable.  All three are shown below.