Networking Tools – CompTIA A+ 220-901 – 2.9

If you’re going to build your own network, you need to have the right tools. In this video, you’ll learn about crimping best-practices, multimeters, toner probes, cable testers, loopback plugs, and more.

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If you’re going to make your own ethernet connections, then you’re going to want a good set of crimpers. These crimpers are designed to take the connector that you’re using and connect it to the wiring or the fiber that will be in place for your network. It’s very common to use these to take the modular RJ-45 connector and connect it into the ethernet cable itself. This is often the last step. Once you’ve run the cable, you’ve cut the ends and you need to add those connectors onto the end, you’re going to want to use your crimpers.

The job of the crimper is to take these tiny metal prongs that are inside of the RJ-45 connector and push them through the insulation of the wires so that it’s connecting to the copper that’s inside of them. This is also permanently pressing the connector onto the cable jacket so that the connector doesn’t easily pull off of the end of the cable.

Here’s what an RJ-45 connector looks like before it’s crimped onto a cable. You can see that they are raised up just a bit over the top of this connector. The crimper is going to push those down. And when it does, you can see those very sharp tines are at the end of those connectors that push into the insulation and make that good, solid connection to the copper.

Once we make the crimp, you can see that we have all eight of the wires that are connected into all eight of those connections inside the RJ-45 connector. You can see that it’s now pushed into the insulation that’s outside of those wires. And you could even see where the connector itself has been pushed onto the cable jackets so that it won’t easily pull out of the connector.

It’s really not very difficult to learn how to make your own ethernet cables. But you need the right tools. You certainly need a very good crimper. It’s also good to have a good pair of electrician’s scissors that are designed to cut through those wires. They’re also relatively small, so they can make the cuts with a lot of precision. And if you have a good wire stripper, that helps as well, especially if you’re working with a lot of coax connections.

One thing to keep in mind is you need exactly the right kind of modular connectors for the wire that you’re using. If you’re using a CAT5 cable, you’ll need connectors designed for a CAT5 cable. If you’re using a CAT6 cable, it’s a different type of connector. They look very similar, but there are some subtle differences on how they’re engineered and how they’re designed. So you want to make sure they match the cable they’re going with. And although stripping the cable and putting the wires in exactly the right spot in the connector and crimping everything down and making sure they all work correctly seems a little difficult at first, once you do it a few times and practice the process, you’ll find yourself making your own ethernet cables in no time.

Another good tool to have in your bag is a multimeter. A multimeter is a device that can tell you about AC and DC voltages and many other capabilities as well. It’s common to use this to check the voltage coming out of the wall. Can easily check the AC voltage and see exactly what you might have going directly into your computer.

It can also check the voltages on the inside of your computer. You can set it to show you all the DC voltages to see how the power supply is operating on the inside of your computer. And you can also use multimeters when you’re working with cables to make sure you have continuity from one pin on one side of a cable to another pin on the other side of the cable.

One tool that I can’t live without is my toner probe. This is a tool that allows you to find two ends of a cable, even if those two ends are in different parts of a building. You simply connect one end to a tone generator. And that’s going to put a sound onto the wire. Then you take this inductive probe and you take it to where you think the other cable might be. This inductive probe doesn’t need to physically touch the copper. It just needs to get very close to where that cable is. And you’ll start to hear the sound of that tone generator come through wherever that cable might be.

Once you’ve crimped your cable ends and you know where those two ends might be, you may want to run some cable tests. Basic cable testing will check for continuity and make sure that pin 1 through pin 8 are all connected to each other. These cable testers are also good to show you if you might have switched any of the wires inside of those connectors. They’ll give you nice wire map so you can see exactly which pin on this side is connecting to which pin on the other side. These cable testers usually provide you with the basics of your cable map. If you need additional functionality, like crosstalk and signal loss measurements, then you’ll want a more advanced cable analysis tool.

If you’re ever trying to run some troubleshooting of a physical interface, it may ask you to plug in a loopback plug. A loopback plug is going to take everything being sent out of an interface and loop it back into the receive interface on that device. And by measuring that, we can see if there were any errors or anything lost between when that traffic went out of the port and when it was received.

Sometimes you’ll even find applications that won’t work properly unless they’re connected to the network. So one way to fool them is to connect up a loopback cable. And it thinks it’s really connected to a larger network when, in reality, it’s simply connecting to itself.

You’ll usually find these loopback plugs with things like serial connections– RS-232, which may be 9 pin or 25 pin. You may find network connections that are loopback cables. There are loopback cables for ethernet and T1, or even fiber loopbacks as well.

These are not cross-over cables. Cross-over cables are designed to connect a transmit on one device to a receive on a different device completely. With a loopback cable, we’re loopbacking to ourself. So this is really designed for troubleshooting and diagnostics on a single device.

If you’re working with patch panels or with punch-down blocks, then you’re going to need a punch-down tool. The punch-down tool is designed to take the wire that you’re using and physically connect it to the connectors that are on the punch-down block. This can be a very tedious process, because you’re taking individual wires and individually punching them down to the separate connections on these punch-down blocks. This process of punching down the wire is not only connecting the wire to the punch-down block, but also trimming any additional wire and keeping it out of the way of the rest of the wires on that block.

Here’s a close-up of a punch-down block. You can see the wires that were added to the punch-down block. If you look closely, you can almost see the tiny copper connectors that are pinching the wire and getting through the insulation. Some of these wires were not trimmed with the punch-down block. Apparently did not have the trimmer there. Whereas others, you can see, do not have that extra wire hanging off the end and they’ve been neatly trimmed to the punch-down block.

On today’s networks, of course, we need tools that can not only see what’s happening on the wired network, but also on the wireless network as well. Wireless networks are obviously broadcasting everywhere. Everyone who’s in the vicinity of the antennas can hear what’s happening on the wireless network.

You can find wireless analyzers that are purpose-made devices. They’re a piece of hardware that you might walk around with. Or they might be a piece of software that you would load onto a mobile phone or onto your laptop. These wireless analyzers are designed to show you where there might be interference on your wireless network. And they might even help you decide where you’d like to direct the antennas so that you get the best coverage for the wireless network in your environment.