A couple of days ago, I reached section "1.4 UTP Cabling" in the "Network Address and Basic Troubleshooting" online course over at the Cisco Networking Academy.
As a result, I drove west down Bell Avenue to the Home Depot in Surprise, AZ.
While at Home Depot, I picked up a 100 foot length of Category 5e Ethernet cable by Southwire, a box of RJ-45 CAT 5e connectors and boots, and a Ratcheting Modular Crimper/Stripper/Cutter made by Klein Tools.
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| Ethernet Cable, RJ-45 Connectors, Crimper |
These are items that I have been meaning to purchase for some time. Since I am making my way through the "Network Address and Basic Troubleshooting" online course, I thought that it was time to buy these items. I thought about buying a LAN cable tester, but I changed my mind at the last moment.
As I made my way through section "1.4 UTP Cabling", I eventually came to the section about straight-through and crossover cables.
The straight-through Ethernet network cable is the most commonly used type of networking cable. Straight-through network cables are used to interconnect different devices, such as connecting a host to a switch or a switch to a router.
Meanwhile, a crossover Ethernet cable is used to interconnect similar devices, such as connecting a host to a host, a router to a router, a switch to a switch, etc.
If you need to use a crossover Ethernet cable to connect a router to another router, for example, then you have to make the cable.
Creating a crossover cable entails stripping the Ethernet cable, separating the individual wires, re-ordering the wires, inserting the wires into a plastic RJ-45 connector, and then use the Ratcheting Modular Crimper/Stripper/Cutter to crimp the plastic connector.
When I took the class for the CompTIA A+ IT certification back at UMBC a few years ago, students were given a length of Ethernet cable, a crimping tool, and a RJ-45 connector. Creating my own crossover cable quickly became a mess.
How could something so easy become so difficult?
Well, when you create an Ethernet crossover cable, the wires have to be in a certain order for the cable to work.
That's where the infamous T568A and T568B wiring standards chart comes in.
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| T568A and T568B Wiring Standards |
To create that Ethernet crossover cable, one end of the cable has to meet the T568A standard and the other end has to meet the T568B standard.
When you buy a length of Ethernet cable, the cable is already at the T568A standard, so half of your work is already completed.
That just means that you have to get the other end of the cable to meet the T568B standard.
While writting this post, I found a short, informative video by Ideal Industries on Home Depot's webpage (just click on my hyperlink) that gives you a step-by-step guide on how to create an Ethernet crossover cable.
All of this information about how to create an Ethernet crossover cable is all well and good. However, there is a catch.
While reading "1.4 UTP Cabling", I read the following section:
Crossover cables are now considered legacy as NICs use medium-dependent interface crossover (auto-MDIX) to automatically detect the cable type and make the internal connection.
Basically, what that means is that creating Ethernet crossover cables is now considered to be obsolete. However, that doesn't mean that Ethernet crossover cables are going away anytime soon. Given that there are millions and millions computers, printers, switches, and routers that are in use today, you will probably need to know how to make an Ethernet crossover cable for some time to come. New equipment, on the other hand, will have this new technology that allows them to function without an Ethernet crossover cable.
In the meantime, keep making those Ethernet crossover cables.
They aren't going away any time soon.
