Physical Connections

0:00All right, in our last skill, we did discuss data signaling and how data might get transmitted across the wire or over wireless or whatever it is. But the point is there's multiple media types that the data can get transmitted through. Now, the other thing that comes up though is how does it get actually on that media? How does it actually get converted into digital signaling? Well, that's part of what we're going to be discussing here. So that data transmission, as I mentioned, it's going to be commonly usually on copper. That's probably one of the most frequent ones because you'll see that in what we call Ethernet networks.

0:33That's where you have a network cable, for example, that plugs into a back of a computer and leads to some other network device, usually such something like a switch or something . And then there's also optical. Normally, you don't see optical going to workstations, but you will see it very frequently up to your network equipment in a server room or into servers or a storage area network, for example, which is a very high-speed storage network. It really specializes in storage. So usually puts a bunch of hard disks in there or something like that that makes them available.

1:04Anyway, there's also wireless, which is probably what many of you are using right now to view this video. So many, many different types of media that can be used. Now, each one of these may accept a different kind of a signal. So copper, for example, is normally going to be some fluctuation in voltage to distinguish between binary bits, for example. There's also radio signals, which we don't really address a lot, although technically wireless networks like your Wi-Fi, technically that is a radio signal.

1:36So you could look at it that way. There's also microwave, which is kind of beyond our scope here for the most part, but it's also capable of transmitting digital and also infrared. And this can be even something as simple as a remote control for infrared. Still transmitting a signal there. I just happen to have it over there because my wife let me have it for the day. OK, so analog transmission. Let's take a look at that one as well. There's also a continuous signal that goes on in analog.

2:07We'll be discussing this here probably in the next slide. For example, if you're on a phone conversation like a normal land line, that land line does not come on, so to speak, only when there's sound being transmitted across the wire. It's on all the time, even if nobody's saying anything or there's not really any sound being picked up. But the way that analog transmission communicates its data is changes in amplitude. So, for example, this is kind of just an AI graphic down here, but you see, and you've probably seen before, how that when you speak, you might speak into a microphone or a sound board or something, you see the little, you know, it kind of looks like almost a heartbeat, but it's a measurement of the volume of your sound primarily or phase or the actual sounds itself.

2:52And of course, those various sounds have to get communicated in a digital format, ultimately, in order to be sent across the wire with the exception of normal telephone conversation over a, or a land line. Although to be fair, a lot of that is actually handled by ISPs, which do convert it to digital, but that's kind of the underscore, but it's a little bit of a roundabout discussion. Okay, let's take a look here at one of the types of signals you'll have. It's something we call base band signaling. Sometimes you'll also see that as a description of a low pass signal.

3:22Now, this would be a direct representation of the original. There's not really a conversion that happens. So normally when you do something like on a strictly a land line signal using something we call plain old telephone service, which is just a copper phone line, that's what's going to happen under this kind of a communication. Now again, I don't want to get into the weeds with this, but increasingly that 's actually kind of going away because it just makes me think of my aunt and uncle that lived on a farm in Kansas.

3:53When I go visit them as a, as a kid, they had a land line. It was actually what we call a party line. So there might be them and several other neighbors that have access to that same land line, but that's not the point of this conversation. What I am making a point of is that was strictly copper that was strict. There was no digital conversion of any kind there. Wasn't that fancy of a system? But I mentioned there was a party line because you could be on the phone talking to somebody and one of your neighbors from a mile and a half away would pick up the phone to try to make a conversation and they'd hear somebody else is already on the line and they'd have to hang up and hopefully wait until you were done or eavesdrop on your conversation.

4:30So anyway, that can also happen. But with this kind of a conversation, it's very common with voice or audio. It could also be with images such as what you'd have with a normal television signal being transmitted over the airways, right? Not a streaming service, not who lure Netflix, but this is actually a television signal that you'd have to pick up with in antenna. Well, with that, there's no modulation or any kind of conversion or anything like that and it's strictly analog. When we say analog, by the way, that hasn't really been defined. So perhaps I should.

5:01Analog is not represented by numbers. Digital would be represented really ultimately by some version of numbers. Analog in many ways is not as precise as that because a number is an actual exact number. Analog follows this amplitude. Okay, so it's varying degrees of something that occurred. It's just represented by something that has continuing variances to change the output or the meaning of the message. So look at this another way. So I have an Apple Watch here.

5:31When it shows me the time, I can change the face of it, of course, because it's an Apple Watch and it's wonderful. But anyway, I can have it show me exact minutes and seconds. Right now it just shows an hour and minute. Oh, no, I have to show seconds when I look at it this way. Anyway, that's a digital representation of the time. But if I change it, you'll turn around so you can see it. You'd say it's 11, 13 and so many seconds. All right. Now, the other kind of a watch face you might have would be an old fashioned one, so to speak, or a very expensive one. They're either old fashioned or nowadays they're very expensive when that actually has an hour hand, physical hour hand and a physical minute hand and a physical usually second hand, okay, like on a Rolex watch, for example.

6:13So you have to pay extra for analog. Anyway, that would just be a visual representation of the time there. It's not something that's converted in a digital way at all. There's also passband modulation here. This will require some kind of a modem, which means to modulate and demodulate, okay? So it converts usually analog to digital and then digital back to analog if necessary. The other thing that might have to happen there is it might be some kind of some form of digital data that has to also be converted, okay?

6:47So anyways, the idea there is the it's modulated to transmit data bits, all right? Now another example of this kind of modulation with a modem would be something that I hope I never have to hear again, that would be the sound of an old dial up modem. Now some of you are too new in technology to know what that is. And I'm not trying to just reminisce for history's sake here, but they are still valid in certain contexts. A modem that what we used to call just a modem would have a landline plug into it, a voice phone line plug into it, and then it would convert analog to digital signals and back again as an early form of accessing the Internet is what we used to do .

7:28We used to be able to do this over copper wires and those modems would transmit that data for us, okay? So again, in this case, it's actually kind of reversed. So I might be working on let's say I'm transmitting a message of some kind of document or whatever, and I make a dial up connection with my modem and I'm going to play the sound here for you in a moment and it gets sent in my computer to my modem here, okay? So this is a digital representation. My modem then would transmit that over copper phone lines if we were at that primitive of a level copper, okay?

8:02And that would be analog, okay? So it's converged from digital to analog and then there would be a receiving modem on the on the receiving end. Maybe I'm making a connection to my workplace, for example, and that modem would then convert it back to its digital format. So it goes from digital to analog to digital. And so maybe this is a file that I'm uploading to a work server or something. Now, if you've never worked with one of these modems, fortunately, we rarely see them anymore. Usually they were capable of only something like 33 kilobits per second, 28.8 kilobits per second, 56 kilobits per second, or at the maximum, usually 112 kilobits per second, and then they would also try to compress the signals to get you a little bit of extra speed there.

8:45But usually they were just pretty darn slow. I got to just tell you. We're talking about kilobits per second, whereas now most home internet connections, for example, are 200 megabits per second or a gigabit per second. We'll talk more about measurements like that later. But a megabit per second is a thousand times faster than a kilobit per second, okay? So we're much faster now than we used to be with these dial up modems. But here is what they used to sound like. Okay, so you may have heard of that sound before.

9:39That's very much like what you would hear also on a fax machine, because the fax machine does the same kind of a thing, okay? Just that these modems were used to transmit, you know, kind of a substitute or an early version of internet. So whatever you might be able to do over the internet, you might be able to do over that modem connection as well. But you could never watch Netflix over it. It'd be way too slow. And after all, that is the gold standard for how fast network is, how fast internet is as if you can watch Netflix or Hulu. Okay, there may also be a combination of all of this. So a good example of this is voiceover IP, which is prevalent in most corporate networks right now, and even in government offices as well.

10:16Most organizations of any size have switched to voice over IP. So it used to be that again, like at my aunt and uncle's house, they would have a phone with a little dialer here. Although actually it was just one of those, actually, that's not a very good picture, but it was one of those circular dialers, you know, would actually be a circle that you would spin around. It would get transmitted over telephone wires, all in analog to whoever the recipient would. Okay, on their phone, on their end, again, the dialer would be kind of looking at this right now.

10:47You probably understand why I actually flunked art class in kindergarten who fl unks that. Okay, anyway, nowadays it starts as analog. And you'll see this in the video down below from from a wallow. Now we have much more modern phones like there's your handset right there with a little keypad over here, you little push little buttons on tape, but your voice is actually analog, right? My voice right now, as I'm speaking, is analog. It's just an amplitude of volume and tone and so on.

11:18But these phones nowadays internally will convert that from, I should put it this way, analog to digital, okay, inside the phone. I do want to point out a small point of discrepancy here. If you have the, I sack of materials for this particular course, networking fundamentals, networks and infrastructure. You'll see figure one point one six, I believe it is, where it shows that the phone does not actually convert it from analog to digital. They show it going into a router, which does that.

11:50No router ever does that. I've never seen a router that converts from analog to digital. That's not its job. Okay. It only handles digital data. So anyway, it gets converted. And this is at least true of Cisco networks, Cisco devices like Cisco phones. I'm pretty sure it's true of all of them. But it gets converted to digital and then sent to the router. So it gets converted in the handset, not at the router. And that's where it's got its digital information encapsulated into IP packets. That's why it came to work across the internet.

12:22And also many of these conversions, as I mentioned earlier, will also implement compression, which just saves on internet bandwidth.

0:00Alright, now the things I'm going to show you on this particular slider probably more than you need to know for the networks and infrastructure exam Nevertheless, it's pretty essential information. I'm kind of surprised they didn't include this So I'm just gonna go ahead and do it here because I think it'll round out your knowledge a little bit better So first of all, let's take a look at the network cables The most common kind of cable you're gonna have is normally gonna be what we would normally call an ethernet cable a short cable that connects say Oh a computer to a switch or something like that. Now a lot of times We'll just call that a drop cable. So sometimes it'll just be called that But anyway, let's take a look first of all at the transmission speeds that will be involved depending upon the kind of cable you're using So when we say speed, what do we mean by that?

0:43Well, sometimes you'll hear that referred to as a data transfer rate or just generally a speed or bandwidth now Yes, there are kind of hair splitting differences between all of those as if I have any hairs to split But we'll all can kind of consider those synonymous for our current purposes, okay So anyway, how do we determine what the data transfer rate is? Well, that revolves around something called megahertz. So let's take a look at this. You see this It looks just like you know a bunch of waves, right? Well, this all happens within a finite period of time So normally when we are talking about computing this would be one second from beginning to end Okay, so in one second whatever I drew here would be one two three four five six seven It peaked seven times. So that would be I guess seven hertz. All right now a mega means a million So this would mean if I had something that was one megahertz in its frequency that would be one million times per second 10 megahertz would be 10 million times per second and so forth and the reason why by the way that This is all a fact. Let me draw in our megahertz again here our hurts Is that the the more hurts that you can the more cycles that is you can squeeze

1:59into a second The faster it's gonna be because each one of these represents an opportunity to communicate You know a lot of times it can communicate on only maybe the rising of the Hurts depending upon the network equipment you're using or more commonly nowadays you'll have rising and falling So the top and the bottom of the cycle it'll be able to communicate on which will of course be double The capabilities other things that will add to this are things like compression So you can squeeze more data into a given second giving it given the amount of megahertz that are available So in terms of bandwidth a lot of times you'll hear megabits per second. What is that about well?

2:34A lot of times you'll heal that for example here that for example in a home network So my home network, let me just show you I'm just gonna go to fast.com which actually I think Netflix puts this together. There's just a quick and easy way to test your internet speed that way You know you can watch Netflix or not. Okay, you never want to try this on a dial up modem like we talked about in our last video But anyway, this is what it is 290 megabits per second notice the lower case be there that is significant. It 's not just the preference of capitalization there And you know a lot of homes are you know 100 megabits per second we could call that broadband as well anything that we would consider a fast Connection they're varying thresholds for that but in my view anything that's a 10 megabits per second or faster is probably you could consider that somewhat broadband or a relatively fast connection You go to most coffee shops a lot of airports Hotels things like that you're you know usually see somewhere between five and ten One of the places I go for breakfast has a very fast connection. It's like 500 megabits per second That's really fast faster than I can get here Corporations you're probably gonna see gigabits per second. They'll pay more for that Of course a lot of this probably coming in because of fiber which is outside of our current discussion But fiber is is

3:51significantly more capable, but also more expensive than what you'll see over copper. Oh, anyway I've tracked a little bit there, but that's megabits per second I said before a lot of corporations will be gigabits per second So a gigabit per second is a thousand times a megabit per second Okay, so that's a thousand times a megabit per second and as I mentioned earlier You don't want to confuse mega bits per second with mega bytes per second Okay mega bits is reference to the speed capabilities mega bytes is More used in terms of storage like how fast a dry how much data a drive can write or read from at a given time Like a hard drive for example that might be measured in mega bytes per second, right?

4:39It's a different measurement, but they sound similar and they're spelled similar It's just the difference is this mega bits and mega bytes and the capital ization there Similarly the same is true with a gigabits per second again These are for networks and these are usually for other things such as the total storage Performance capabilities that you'll see with various devices oversimplified for now But that that's the main point there. Okay, so for networking it's gonna be the lower case B in both cases The actual throughput is usually slower than the rating so for example going back to my speed test I shouldn't have closed that open it up again here. I'm paying in my case I'm getting 290 megabits per second there 300 okay. I'm paying for 250 megabits per second So I'm kind of getting bonus speed out of Cox C O X my Internet service provider they kind of generous that way I usually get really good connections up to a point I actually at one point paid for one gigabit per second or you know gigabit E sometimes we'll call that as well Internally here anyway, I paid for that, but it would never get faster than 300 megabits per second anyway Sometimes it might be able to get up to 500 But we're usually not and 300 megabits is plenty fast for me and for what I'm doing so I just cheaped out and

5:55Back down my plan to the 250 megabits per second and I get a little bit of bonus speed out of it Okay, so anyway the fruit put is often slower than the actual rating, but in my case, it's actually a little bit faster So that's a little bonus there now. There's something called unshielded twisted pair. What's that about? Well, you'll see some cables here coming up Where there's a twisted pair of wires actually let me kind of get a free preview there real quick So you'll see some twisted pair cabling that you see right here. Okay, it's one pair That's wound around in twists and then another pair rounded around in twists another pair round and round in twists Huh, you know, I just realized something funny about this diagram. They are totally missing one complete color They're missing brown white brown. I don't know why they're doing that that way , but anyway, they missed it So anyway, there's another example over here real again see twisted pair c abling But anyway unshielded twisted pair this means it does not have extra protection will return to that here in a moment Okay, and it's the most common that you'll see very likely if you have an ether net connection to your computer, it's gonna be unshielded twisted pair if you have a switch in your home network Maybe that's integrated with your cable modem for example from your ISP very likely using unshielded twisted pair there unshielded twisted pair is cheaper than shielded twisted pair or STP which

7:13again will cover later Anyway, that's very often used for a UTP category. This is another reference term Cat five is usually what we call it. We don't usually say category. We say cat five cat five e cat six cat six Say so cat five is capable of up to a hundred megabits per second and remember we talked about the hurts, okay It uses a hundred megahertz per second in order to achieve that speed now The fact that both of these are hundred is purely coincidental There's not a direct correlation to from one to the other okay Is you'll see right here with cat five e which is what I have in most of my home because I built my home 20 years ago and I Snuck in at night and evaded the security guard and for the neighborhood and Strung my own cat 5e throughout my house So I have ethernet jacks and most of most portions of my house anyway cat 5e is also capable of a hundred megabytes per second at 100 megahertz, but it has an expanded capability that goes up to 1 gigabit per second at 350 megahertz per second so cat 5e is obviously got a higher capability much higher Cat six or six a is also capable of a thousand megabits per second by the way a thousand megabits per second and One gigabit per second for the same thing okay

8:30Because a thousand megabits per second is one gigabit per second It's a thousand times faster when you get into gigabits right anyway That's at 250 megahertz and again because they figured out a way to cram more Cycles within a given second they can stuff more data in that wire in that transmission 10 gigabits per second again That's now going to be 10 times faster than a thousand megabits per second or gigabit per second and that they were able to squeeze in 500 megahertz okay, and this standards are continuing to improve and give higher speeds Do keep in mind that just because you have a cable. It's capable of let's say a gigabit E Let's say you're using cat 5e just because you have this does not mean you're getting that speed You may have switches in your network that are only capable of a hundred megab its per second So you're gonna be throttled down to a hundred megabits per second even though your cable is potentially fast Likewise you might have gigabit E switches which is a thousand or one gigabit per second speed But your cable might be cat 5 cable and it's only capable of 100 megabits per second so everything from A to Z Throughout your data path there has to support the same speed in order to get

9:47the fastest Pass us one otherwise they usually default down to whichever device is the slow est all right Our next nugget will take a look at more specifically at the cable

0:00Alright, so now let's further address twisted pair cabling. There's a couple of different types of twisted pair cabling, unshielded twisted pair or UTP or shielded twisted pair as you can see here, which is STP. And the basic idea here with twisted pair cabling in general is that it provides less attenuation. See, every time let me go to the diagram here. Again, there's a fallacy with this diagram because they're missing a whole twisted pair here. It should be brown, white, brown that's missing there. It should look exactly like that. The only difference will be the shielding here, which I'll discuss again here in a moment.

0:32But regardless, notice that these twist around each other. You know like how a bread twist? How you twist on that on the bread and keep it fresh? Well, this won't keep your bread fresh, but what it will do is keep your network in good shape. So you buy the cable where it's been manufactured in such a way that all of these are twisted and there's so many twists per inch. And as this cabling has advanced over the years, they've gotten more twists per inch, which provides better protection against cross talk and attenuation.

1:02The cross talk is where you'll have this cable may lie alongside of other cables or close to electromagnetic fields or other things that could interfere with the signal going across the cable here. Well, by twisting it like this, the more twists you have in it, the more resistant it is to that type of interference. So that is why the twisted pair is there to avoid cross talk and interference. Now unshielded twisted pair. I think I mentioned this before is probably the most common form of ethernet that you're going to see right now.

1:36I do want to point out, I'm not going to really delve into this much, but in the eye triple, excuse me, in the isaka materials here, you'll see reference to 802.3, IEEE 802.3 standards and anything that starts with 10 base. Those mostly refer to coax cabling, which is the same look. It looks the same. It's not exactly the same, but it looks a lot like the cable that comes into your house that you plug in your television. Okay. That's really old. I still don't know why isaka is insisting on including that kind of information .

2:10I would say you don't need to memorize any of that. If you want to just skip that part, you'll be fine. I don't think you're going to run into that anywhere. I haven't seen it in 15 or 20 years. So again, you know, a little bit of a history lesson from I sack on that one. But regardless again, here you're normally going to see unshielded twisted pair . It's relatively inexpensive, which is another reason why we use it. It's got a maximum length of 100 meters, which is also known as 328 feet. Okay. So the other kind of cable that you might run into and we're not really addressing cat five cat five, he cat six cat.

2:45There's also a cat three, which is one of the earlier implementations. And there's also a cat seven, we're not really addressing that particularly. And that's address of the capabilities of those cables. Really mostly addressing kind of the physical cable right here. There's also shielded twisted pair or STP as I mentioned earlier. This is less common. And one of the reasons for that is because it's also more expensive. Now what you can see with this, and let me go back to the diagram from this article. This is from tech target, which is normally they have really good materials except for this graphic, which is missing a posted pair.

3:17Like one thing that this does get spot on is that with a shielded twisted pair and an unshielded twisted pair, they both have this outer jock or outer jacket in common. Okay. And they will have the twisted pair cabling themselves, which also have a thin plastic layer of insulation around each one of them. But the shielded twisted pair will also include an outer shield, which is usually like a foil type of a material and an, an a pair shield. So each one of these pairs will also have a shield around it.

3:51And again, that's going to be kind of like a oil material. In fact, let's just look for it. We go into images here. I think we might see some, some better pictures here. Okay. So, oh, look, there's that article I was just talking about. Okay. Anyway, so you can see over here above my head, it's kind of hard to see down here at the bottom. There is a, there is a jacket that goes around all of the twisted pairs. And then each one of the twisted pairs will have its own dedicated shield as well, which again, it's much like a kind of an aluminum foil type of material. Now, let's get to the point of why we would use that.

4:22Okay. Since it's more expensive, you don't want to just use it everywhere. You're going to use it where it makes sense. It's going to protect against things like environmental factors. So electromagnetic interference, there might be factory floor equipment. Maybe there's a, a centrifuge somewhere that's spinning up a lot of EMI. A lot of that heavy duty factory equipment has a pretty strong electromagnetic field to it. Also, it could be running alongside cable or possibly too close to other kinds of electrical cables, other kinds of communication cables, high power cables, even ballots up like in the fluorescent lights above your head.

4:58There are ballots there that if you run unshielded twisted pair too close to it , it'll start to get interference. So you'd probably want to put shielded twisted pair in that kind of a context. This also does require grounding. Let me go back to that, I'm going to enter in RJ45 here as well as a search term. And hopefully we'll get a good picture here. Oh yeah, here's, here's one here. I think it'll work out. All right. So we take a look at this article from Platinum Tools and I, oh, they want me to print their article. I don't know. Thank you. Anyway, you might be able to see here that this plug, okay, normally they're just clear plastic.

5:34This one is metallic. It's got metal on the outside and these are going to be grounded. Okay. So they're characteristic of that type of shield. No, I don't want to subscribe. Thank you. And then this article here does talk a little bit more about that as well. If you want to look further into that, I will again link that down below for your reference. Now here, this is just a photo I took of some cable I was doing that long ago myself. So I thought, you know, I'm probably gonna have to teach this someday. So I thought I'd just snap a picture of it. This is the cable. This is unshielded twisted pair.

6:04And you can see there's no metal in the plug right here. By the way, it's not to scale. It's not as, you know, that much bigger than my head. Either that or my head is ginormous, which maybe that is the case. Anyway, you've probably seen these before. One might be in the back of your computer right now. This one's not shielded. So there's no metal on it. There's no foil down here as well in the insulators. And what happens here is you use a special tool, actually I have one over there .

6:35Let me show you. Within a cable. This is what I just now assemble. I haven't finished it yet. What I have to do yet is I still have to crimp this cable. There's a special tool you'll use. And what it does is it takes these metallic parts right here, which are kind of in blades. And they have teeth in them that bite down into the cable and make contact piercing this outer shell, this outer insulation right here. This, what I'm showing you here is a little bit more of a modern kind of a plug . It used to be that they would terminate right at the very end.

7:06I can't see that very well. It would terminate at the end of the plug and it made it a little bit more difficult to align these up. By the way, sometimes you have to have the dexterity of one of Santa's elves to be able to get all these lined up just right because you have to untwist them and stick them in there and just the right order and stuff like that. But anyway, now what I'll do is I'll take this crimper tool, which by the way also has the wiring diagram on it off. You can see the colors there on the very end of that. Just for a quick reference, if you need to look at it, you can. Anyway, I'll take all of that and put it into this little crimper right here and then just squeeze down real hard.

7:39Can't show that on camera because my shoulder, sorry, it's just having a hard time with this. And there's also a blade inside of there, which will then trim off those excess ends. Remember they were sticking out of the end earlier? Well, now they've been trimmed off by this crimper tool. So there you have it. When you're done, it should look something like what you see here. Exactly because these are in a specific order, which again, I'll address later on. Okay. So anyway, this end that we see right here, this is known as an RJ45 registered Jack 45.

8:10If you have copper telephone lines, that would be about half this size. And it would only use four wires instead of eight. Here we have eight wires total. RJ 11, which uses four wires is used for copper telephones. Anyway, this is what you'll see there in networking and the scheme can be something you'll see is five 68 a five six D eight B or there's also an abbreviation for this. You might also see it T five 68. I just usually call it five 68 eight or be anyway, you'll see that again in articles I'll reference to you.

8:41But the main thing you want to do is you have to have the same layout, whichever one you're using, both of these are slightly different. You have to have the same layout on both ends. Okay. Now, a lot of government offices in the United States government require this in cabling the five 68 a. It's actually a little bit of an older standard. I triply replaced that for the most part with five 68 B. Gosh, I think it was in the nineties. So it's been a while, but after all, it's the US government. They don't change very fast.

9:11But for standardization, you should have across an organization the same wiring standard. You don't want to have, you know, one part of your network that uses a and then the other part that uses B because the order of these cables is different in each one of those, which again, I'll show you. And regardless, I'll give that a moment, but you also have one which will connect into usually some kind of a device, maybe a computer. And the other end, which could connect into a hub, which we'll talk about later on, there's kind of antiquated now. I don't even know if you can buy them anymore, but you might see some really old networks.

9:43Switch is probably the most common. And then it can also plug into a router. There's also a crossover cable, which I'll talk about here in just a moment. So first, let me talk to you about this wiring difference between T568A versus T568B. Okay. Here is the order in this article. Again, I'll link this down below. Fluke networks is very well known for making good network equipment. It's a network test equipment. They make things like this cripper that I was showing you earlier.

10:13This isn't one of theirs, but very similar to that. And all kinds of good stuff. So very well known in this space. Anyway, 568A, as I was mentioning earlier, and then 568B, which is where I normally use, in which a lot of commercial organizations use. And you just kind of memorize the order of this. I could just do it without even looking. You can see from pin one up at the top, it's orange, white, orange, green, white, blue, blue, white, green, brown, white, brown. Okay. We just kind of becomes a mantra. Everybody that works with networking just kind of knows that.

10:44The difference, if you want a quick mnemonic for this, besides memorizing that order, is that 568A just simply switches the green cables and the orange cables. Okay. That's the only difference. If you look at it and study that, you'll see that. Okay. It just switches those orders. Now there is also a crossover cable. Let me talk to you about that. A crossover cable for conventional ethernet networks will use 5T 568A on one end and 568B on the other end. Now, what is a crossover cable?

11:14Why would we want to use it? Well, first of all, we don't use it very often anymore. It's kind of becoming a little bit more antiquated. But the main point of it is that if you connect two devices, for example, without a switch in between, then the transmit and receive pins or transmit and receive cables will be in the wrong place. So if I have just, let's just say it's a PC here and a PC here and we didn't have a hub or a switch or any kind of network equipment. We just wanted to run a network cable between the ethernet jacks on both of these computers.

11:46One would have to be 568A and the other would have to be 568B because otherwise , the send and receive signals would get mixed up and they wouldn't be able to transmit any data properly. You can also use it to connect switches to one another. So if you have a switch right here with all of its little ports on it, I was put three in there because I don't want to draw a bunch. And then you had another switch here that you wanted to connect also to one to another, then you could connect a crossover cable right here.

12:20And then this would effectively be a single network, at least initially. There's other things you can do to break that up, like something called VLANs, which we don't discuss quite yet. But essentially, I've now created a single network out of these two switches by connecting them together, using a crossover cable. Reason why I said that's kind of become a little bit older is because most modern switches can auto sense. So I could connect a conventional cable that let's say was 568B on both sides and the switch will say, oh, hey, this cable has this coming out of the send and this coming out of the receive and it will automatically be able to adjust itself electronically internally in those switches.

13:01So for that reason, I really wouldn't need a crossover cable. But like I said, you might use it to connect two computers or devices together without a switch or hub or if you want to connect two hubs together, something like that. And even the crossover argument that I was making here, that's kind of getting older as well because we have lots of other ways to transmit stuff now. First of all, most everybody's on Wi-Fi where this is not an issue at all. You know, use cabling for that, at least not for the host at the host level. And even barring that, you know, if you had two laptops, for example, you probably are going to use Wi-Fi there or you can even use Bluetooth.

13:36There's ways to create kind of a personal area network or a pan between two devices for temporary purposes that transfer a file or send something. And again, you wouldn't even need a crossover cable for that. One other thing I have to bring up and I don't mean to bag on isaka, but if you 're looking at their materials, you'll see figure 1.21 and it says 568-b standard and then it will say TIA, EIA, that's really the full acronym there. We just don't usually use it.

14:06We usually just say T. 568-b crossover cable and then it has a totally different pin out than what I just described. Okay, because I had 568-a on one side and 568-b on the other side. So on the left here, that is a 568-b. On the right here, that's not 568-a. So what in the world is this? Well, that's what we call a four pair crossover for gigabit, but they don't specify that anywhere in that diagram or in the text above or below it.

14:36Okay, so that's a little more of an unusual or a different kind of a crossover cable for which there's no explanation in their materials. So I point that out because once again, you don't need to memorize that pin out , even though it's in the book, you don't need to memorize it. And even if it's not on the exam, I would memorize the pin out for 568-a and 5 68, as much as anything because you're going to be using it. You won't be in IT for very long before you'll have to put some cables together or identify what kind of cable you have and so forth.

15:06And then finally here, I'm going to address plenum-rated cable. So unshielded twist-appeared jacket is normally PVC plastic, which in a fire is very bad. It has toxic emissions in a fire. And plenum areas are very often in the ceiling and they are usually above the sprinkler system. So if you have a drop ceiling, you'll probably have some sprinkler heads popping out of there, and then some of them are up and there also above the sprinklers will be your plenum-rated cable up above. Plenum-rated is non-toxic in fire.

15:39So that's why it's going to be better up there because again, you have to pay a lecture for it, but it's just safer. It might be tough-lawn material or a very low-smoke type of material.

0:00Alright, so we're called from our last nugget that we took a look at twisted pair cabling. Alright, remember it's got a distance limitation usually of 100 meters. And the other part of that is that it's susceptible to electromagnetic interference, machinery, anything that creates an electromagnetic signal, light ballasts, you know, all kinds of things like this. However, when it comes to fiber optic cable, we have some characteristics that are much more advantageous there and then overcome a lot of the limitations of copper.

0:33The only problem is it's more expensive. Okay, everything costs money, right? But it is not susceptible at all to electromagnetic interference. It's just light. Light and electromagnetic interference don't really, I don't know, exist on the same spectrum, so to speak. I can't really interfere with one another. Probably oversimplified, but you get the idea there. Now, the signals there will be transmitted digitally. It's very literally digitally and it's not something that gets converted from analog to digital or something like that. Purely digital and the signals travel at two thirds, the speed of light.

1:06So the speed of light is a hundred eighty six, no, hundred eighty seven thousand miles per second. So whatever two thirds of that is, let me look it up. Oh, fiber optic cable travels at a speed of around 124,000 to 144,000 miles per second. So that's, yeah, that's probably around somewhere around two thirds of the speed of light. A lot of different reasons for that. The light is traveling through some kind of a medium. It's not unimpeded light that travels in a vacuum. So that's why it's two thirds of the speed of light instead of actual speed of light.

1:40The core is plastic or glass. Now when you take a look at this, the fiber optic itself is measured in terms of microns, which is a millionth of a meter. That's really not visible. The reason why you can see, I just, this is just a graphic you see up here. But the reason why actually you see the fiber optic there is because it's actually enclosed inside of a plastic cladding or a plastic kind of a jacket that gives us the ability to handle it and to manage it and stuff like that and bend it.

2:13But it is, as you can imagine, also more fragile, especially if you're using the glass core there. So you do have to be more careful with it. It's also difficult to splice or to tap and it's more expensive than unshielded twisted pair. This also causes some problems, which is not really related to fiber optic on its own, but it just so happens that as you look at a map of the world, we have a big body of water right here, don't we, he called the Atlantic Ocean. Well, we have to have internet that goes back and forth between, say, Europe or the Middle East or India and America, let's say in this case, how does that happen?

2:53Well, we have things like satellites and things like this, but there's also undersea cables that transit between America and Europe. And I thought I'd just actually go ahead and Google this. Okay, so there's this submarine cable map. And I don't know that all of these are fiber optic particularly, but many of them will be. You can see here that there is a lot of cabling going back and forth across and do also notice this whole all of these cables down through here up through North Africa.

3:25And as we zoom in here, you see a lot of really tight concentrations of cables there. Well, the time of this recording, there is an awful lot of conflict in the Middle East. And some of these are getting vandalized right now. We don't know who's doing it or what's going on, but some of these are getting cut and they're extremely difficult, as we mentioned earlier, to splice, repair, replace. And I'm sure also very, very expensive. Some of these should identify as fiber optic. Let me see if I hover over. I can't seem to put my pointer on exactly one.

3:56I just saw one not long ago. But anyway, anyway, that's kind of what's going on right now in terms of under sea cable. And you can see how significant that is in terms of keeping the whole world connected here. Now, I don't think you'll need to know these specific items for exam purposes, but just so you know, there's a couple of different types. Actually there's several different types, but a couple of major types would be a single mode cable. This would be very useful for things like internet backbones. So from your ISP has very likely gotten, you know, many different single mode cable backbones through different parts of his service area.

4:29It can also be used for phone systems, television, things like this. So, for example, Verizon, which I think is the largest cellular provider in the United States. They are offering something called Fios, it's F-I-O-S Fios, and it's fiber optic internet. I'm assuming that that's probably going to be using this single mode kind of cable. It's supposed to get really super high speed internet and it's not available in my area. So, so I'm kind of bitter about that. But anyway, it's a single signal, well, that's a tongue twister, single signal that's generated by a laser, right?

5:06The speed capabilities are between one gigabit per second and 10 gigabits per second. Now, these numbers are kind of common bandwidth capabilities. I'm sure there are ways to get it to go faster or there are other standards maybe that are new that are going faster as well. But that's kind of generally what you'll run into. And it's 8.3 to 10 microns. Remember, a micron is a millionth of a meter. So I don't even know if that would be visible. I don't think that would even be visible to the naked eye, so to speak.

5:36But again, you can see it because it's inside of that plastic cladding usually and that illuminates because of the illumination on the actual fiber itself. The distance I've seen all different kinds of distances in terms of its maximum capabilities, probably has a lot of different factors involved. But the distance is going to be in terms of kilometers, not in meters in most cases. If you refer to the isaka materials, which are actually pretty good on this topic of fiber, you'll see that some of the standards here, 100 base FX, 100 base X and 100 base LX, which are all different portions of the 802.3 standards for fiber, they're usually going to be pointing to one that's 512 meters, 500 meters, 550 meters, that is, you know, 3 kilometers, 10 kilometers and so on.

6:24I did see one that was capable of 1000 kilometers, but it's not in the isaka materials. So I'm assuming that's the kind of cable that would probably be used under seat , but I don't know that for a fact, but you would imagine. There's also multi mode, whoops, I dropped my pen, there it is, multi mode. This is going to have a larger size core, and it will jump to the end here. It's still 50 to 100 microns, still really tiny, but a larger core. And it can have multiple signals that are generated, not by laser in this case, but by LED.

6:55So a single larger core can have multiple different signals in that one core. You'll often see this in server rooms or maybe between campus buildings. This is not going to be usually in terms of kilometers, but you actually go to the end here again, 550 meters is the length that we can see for that. And it gives us about 10 gigabits per second.

0:00All right, now let's take a look at certain types of connectors that you can use in fiber optic cables now it's gonna connect to fiber optic switches and fiber optic network equipment But on the local side you'll have something possibly like this as well here Let me zoom in actually had this device for a few years now But it's a network card it looks like transparent because it's green and I use green screen recording So ignore the fact that it looks kind of transparent there But anyway This is a network card and you can see here that it's got room for the connector that would go inside of there And we'll get to the tips that we use the connectors that we use a little bit later on But inside of that you can see there's room for two connectors that would be an SC connector That would actually be duplex SC connector because you can see you can put two in there another news Looks like you need a manicure. Okay, so let's take a look at the various types of connectors There is a first of all an ST or straight clip type. Oh, there's my network card behind me I'll move that up. That's a better view the connectors there anyway, but With the ST connector that would be a twist and a lock Sometimes people use a mnemonic for that to remember it stick and twist ST

1:16stick and twist because what you do is you twist and lock those You don't pop and lock like you break dancing, but you do twist and lock and hopefully it's every bit as entertaining This is very popular and very easy to use very commonly used in LAN networks and let me show you a picture of some of those here's one right here I just kind of googled for this article But you can see here that what you would do is you would stick this in okay that the micron measured Pybroftic cable remember is in here But it's got a plastic cladding that goes around it and then it has a twist lock So on the receiving end is gonna be a little post that when you twist this it locks into this little final notch that you see Right here, and that's how that connection is made now There's also an SC connector which is also known as a subscriber connector or square connector And for this we would say it's a stick and click okay, so You don't twist it or anything you just put it into place and you press put a little pressure on it And you'll actually feel it click into place Some of these are held in just by a little notch and and by pressure And so if you want to remove it you just pull it out a carefully pull it out But otherwise you'll get that confirming a little click some of them will also be latched and with those you'd have to press

2:31Down on a little latch in order to be able to release it this can be used in single or multi-mode and then moving on We would also have a loosened connector or an LC connector. I don't have an m ama mnemonic for that one I don't think they're around anymore But loosened used to be an early telecommunications provider and they used to be pretty big There's also a term a local connector What you'll also sometimes associate with this and it's a mini form factor and it's used with fiber channel adapters Sand networks and gigabit e network adapters and I can reference this article for you here as well But they have a pretty decent Little photo here of the various types. There's the LC connector that we were just talking about the loosened style connector Then there's the ST connector We talked about earlier remember stick and twist and then this one right here stick and click I don't know if you can see it But I said you can feel a click on it right in here There's a little bit of an indentation right there where it would kind of click into place the loosened connectors This is one that you usually have to press down on that little connector right up there at the top In order to release it. So those are your most common types of fiber optic connectors

0:00Alright, let's take a look here at a validation to summarize everything we've learned here. And here in this situation, you need to provide cabling solutions for your company, provide the best solution in each of the following scenarios. All desktop computers will use cables instead of wireless network connections. The desktop computers are ordinary desktop computers in a typical office environment. You have switches which are capable of up to 1 gigabit per second, which type of cable would be best in this situation.

0:30Let's start with shielded twisted pair copper. Well, that would work, but we haven't really discussed anything or shown anything in this scenario where there's electromagnetic interference or a real need to use STP, and that's more expensive. So since this is an ordinary desktop computer in a typical office environment, that does not seem like the right solution. Fiberoptic single mode. Now, remember fiber is used for extremely high speed. Normally, desktop computers in an ordinary desktop computer typical office environment, you're not going to need that.

1:04That one might be the case in certain other situations, but any of these fiber solutions is not likely to the correct answer. However, unshielded twisted pair is inexpensive, perfectly capable of a gigabit per second with modern cable, and that should be a good answer for you. Your company has a factory floor where there are a number of heavy, heavy machinery, manufacturing, devices. These machines emit quite a lot of electromagnetic interference. You have instructed to use an inexpensive solution as possible.

1:35I'll reword that in the final. Which type of network cable should you use here? You get the idea. We're trying to bypass or protect ourselves against electromagnetic interference, but we also want an inexpensive solution. All right. Unshielded twisted pair would sync us. That would be very susceptible to EMI. We don't want to use that at all. Anything that's fiber is going to be more expensive. It's not susceptible to electromagnetic interference, but it's expensive. Shielded twisted pair copper would be protected against EMI, and it would be the less expensive of these three bottom options.

2:12So there's your answer. Now, your company headquarters is a large multi building campus. Some of the buildings are separated by more than 100 meters. The fastest possible connection between all buildings and cost is not a significant factor. I don't know what's going on. I'm using voice texting for a lot of my typing, because of my whole get up right here. So that's probably why some of this looks kind of weird. I'll reword this so it makes better sense. Anyway, I think you get the idea. What type of cable would be ideal in this situation?

2:44So the key idea is here, multi building campus. The buildings are separated by more than 100 meters. Remember there's a network cable type that has a maximum of 100 meters. So if we're going more than that, we need something different. The fastest possible connection between all and cost is not a significant factor. All right. So let's take a look at anything that says coax. This is what looks like your TV cables. No, we don't want that. Remember that's old, slower. It's just not a good solution in almost any context anymore.

3:14So anything that says coax, we're going to rule out immediately. Mobile mode fiber, that's useful for up to kilometers. It's very often used for television, internet backbones, things like this. And it would do this solution. However, when it's more dedicated towards this type of a solution would be a multi mode fiber. Remember we use that in server rooms and in between buildings and on a big campus, that sort of thing. So multi mode fiber is most likely a better solution for you in that context.

3:46OK, I will try to clean up some of the wording on some of these. Hopefully you got what I was trying to say. And I will see you in the next skill where we talk about wireless networking.