Join Greg Sowell for an in-depth discussion in this video Terminating a Cat 5 cable, part of Foundations of Networking: Network Media (LANs).
- Terminating a Cat 5 cable is a common task for most network engineers. Mastering this process is essential. Over time, crimping will become second nature, and a handy tool in your networking career. Using the right tool for the job can really make or break the process. The first tool you absolutely must have is a cable crimper. Crimpers attach the mod plug to the wires inside of a cable by compressing the metal pins on the connector onto the wires. When it comes to crimpers I prefer ratchet crimpers. Without the ratcheting action I never quite know if I'll squeeze enough or if I squeeze too hard and crush the connector.
With each ratcheting step the crimpers lock into place. I know when I've completely crimped a cable because the tool will unlock. I also need something to strip the jacket off the cable. Specialized cable strippers pinch the cable, then allow you to spin them in a perfect strip, but I prefer just to use regular wire strippers. Cable strippers cut Cat 5 quite well, and because I never quite know what I'll be doing from day to day, I use a single tool for multiple purposes to keep my took bag small. Normally, I like to strip back the jacket on the cable about an inch and a half, which is purely preference.
It gives me enough space to easily work with the cable, but not so much that it takes forever to untwist the pairs. I'll apply light pressure to the cable and twist the wire strippers. There's something of an art to cutting a jacket with strippers because you want to squeeze hard enough to cut the jacket, but not so hard that you damage the wires inside. If you nick the wires you could severely weaken them, which can cause the cable to fail, so be careful. You can now see each twisted pair. There are 4 solid colors. Orange, green, blue, and brown. Each has a white and colored stripe wire around it.
The color stripe matches the solid color it is wrapped around. I'll push each pair away from the others and untwist the wires all the way back to the jacket. Once I untwist, I'll straighten them out. This will make it easier to insert them into the connector later. I just pinch each pair and pull towards the end. Now I need to arrange them. There are 2 EIA/TIA standards, 568A and B. B is the industry standard. Physically speaking wire is wire. You can terminate a cable with whatever crazy color pattern you like.
As long as the same on both sides, it'll work. Standards exist so that when you terminate a cable on one end of the building and someone else is terminating on the other end, you don't have to confirm. As long as you're both using the standard, your cable is going to work as expected. The color code for 568B is orange-white-orange green-white-blue, blue-white-green brown-white-brown. The color code for 568A is green-white-green, orange-white-blue, blue-white-orange, brown-white-brown. When you hear someone say this out loud they might transpose the terms when they refer to the white cables calling them white-orange, or orange-white.
The difference is nothing more than audible. I say orange-white because that's the way I learned it. While some of my colleagues say white-orange. When I'm arranging wires I do it looking from the top down and left to right just like reading a book. I pinch the cable between my pointer finger and thumb where the jacket sits halfway on the pointer finger. Moving each cable into place can be a bit tricky and requires some twisting and pulling. Once they're all in place I bend them back and forth and pull them up and down to align them as precisely as possible.
I'll want them nice and tight so they'll slide into the connector. Before I cut them I give them one last look over to make sure they didn't move on me. I've made so many cables that I can go by feel when cutting the wires to align. I pinch the wires tight with the jacket still in the middle of my pointer finger, then clip the wires off where they poke above my finger leaving about 5/8 of an inch exposed. Now, I'll orient the RJ45 with the tab facing the ground. Pinching the jacket right where the cable exits, I'll slide the wire into the connector gently wiggling them side to side.
Once it's in, we have one more push rocking it back and forth. From the end of the RJ45 I can see the ends of the cable right at the front of the connector. Looking from the top of the connector I'll also verify that the jacket is inserted past the depression tab. When I crimp the connector the metal tabs in the ends get pushed down and bite the wires. The little retention tab also gets pushed down and bites the jacket helping to hold the connector in place. With the ratcheting crimpers, I'll slide the connector in and hold it stable, squeezing the crimpers until they release.
To finish the cable I repeat the process on the other end and use the cable tester to ensure everything terminated properly. To make a crossover cable, I would terminate one side at 568A and the other side at 568B. Crossover cables are traditionally used when connecting 2 like devices together without using a switch, so router to router, switch to switch, or PC to PC. Modern equipment supports auto MDIX allowing the port to sense if the cable should be crossed and automatically managing that, which all but removes the need for cross over cables.
Terminating Cat 5 is as much an art as it is a science and can take some time to master. Still, nothing is more satisfying than seeing a link come up from a cable you made yourself.
- Exploring cable types
- Creating coaxial cable
- Terminating Cat 5 cable
- Mitigating EMI
- Setting up wireless LANs
- Comparing Wi-Fi frequencies
- Securing a wireless network
- Using fiber-optic cable in LAN and WAN applications