31 hours 29 minutes

Video Description

Telephone Lines This lesson covers telephone lines, which are the most commonly used infrastructure in connecting to the Internet. It saves costs for running lines as they are already pre-existing in many places and are very useful for transmitting data connections via a DSL connection.

Video Transcription

So when we're talking about our win connections, we're talking about our wide area network connectivity and especially when we're talking about individuals. Connective ity to the Internet are most commonly used. Infrastructure is going to be our actual telephone lines. Now. Why do we use our telephone lines? Well, there's a lot of reasons and one of the major ones being that the
that the infrastructure is already there.
We've already spent time taking telephone lines and putting them to almost every house in AA. Lot of our country's almost every almost every location has a telephone line to it. So we're gonna use this preexisting infrastructure
to carry along data for our wide area networks.
It saves us costs on running additional lines. It saves us cruise and training to train these cruise. How thio fix these additional lines. We just make sure that as long as our telephone lines are running, so is our So is our data connection. So,
our telephone lines, we have a couple of different types of data connections that we're going to send over them. We have our pots slash p S t n. We have iest bien, and we have our different BSL connections. Now, by far R. D s L connections gonna be the most common that we're going to see in to date by today's standards.
But as different companies start running dedicated lines
just for data and they start running lines like such as Verizon Fiber or Google Fiber or different different companies lines dedicated just for an Internet connection We may see a shift start to very slowly, of course,
but start to change toward other other methods and using D S L less and less.
But as of now, it's still very common standard because we're using this existing telephone line infrastructure.
So our first and sort of our grandfather to our our data that we're gonna carry over our Internet is going to be pots and P S t n these air, also known as our dial up connections. Now our pots stands for plain old telephone service and P S T n stands for public switch telephone network.
These are both dialect networks that use that device that we're that we're very familiar with
our modem.
So if you see saying a test question that says which type of what type of Internet connection utilizes a modem and you see pots I issued E N d s l and A. D. S. L. You want to go into choose pots because that's what's going on are plain old telephone service is what's going to use that modem.
So what does that modem do?
our telephone lines are in our pots network are going to carry data through analog means and we've seen before that when we're taking a look at our analog signals are analog signals look like this.
They're wavy. They can have tiny little tiny little changes or trying to small distortions between them. That's our analog signals are digital signals on the other hand, which is what our different computers communicate with look like this.
Whereas an analog signal can be a kn analog signal can have a large range of different waves and different, different finesses to it. Our digital signal is either is just gonna be a signal of either on or off
s O. They're two. They're two very different signal types are analog in our digital, so we need a device that changes our digital signal signal from our data from our from our actual computer to an analog signal that can be sent over our telephone lines. And that's what our modem does. Our modulator de modulator
changes that digital signal to an analog signal
than it actually calls a phone number at our Internet service providers location and sends it that analog signal to the Internet service provider who then takes that signal, changes it back to digital and then passes it alone, gets our data and passes it back.
Now, our pots psst! And dial up is going to run in a max rate of about 56 killa bits per second. So, again, this is sort of our grandfather Early early age, beta network over telephone line. So it's gonna run at what we're gonna look at is gonna be our lowest speed of the bunch.
Our next step up is going to be I S d n now r I s d n is going to stand for integrated service is digital network and R I S D in rather than using a modem is going to use telephone lines and a terminal adapter. Now we all remember about well, those who may have experienced dial up may remember
the days when
you could either search the Internet or you could call your friend on the phone. But you couldn't do both at the same time because of the way that the modem used up that telephone line R I s d A is gonna be a little bit different because that terminal adapter is going to send the data in a way that we can actually use the phone and we can navigate through the Internet at the same time.
Now, R I S d n is going to utilize to data channels per per our standard line. In each of those data, channels run at 64 kilobytes per second. So our total max speed for standard I s t e N is going to be 128 kilobytes per second. So obviously
the more channels the better because each data channel can carry
64 kilobytes per second speeds.
if we're not a if we're not a small office or home environment, we may need for a large organization Maur data channels, because we need more data we're pushing through. We're not just we don't just have two people on the Internet. We have 200 people that are trying to connect to the Internet.
So rather than having these two data channels PR, I, uh, that's used for large organizations. Standing for primary rate interface is an I S B. In a nice Indian connection type that has 23 data channels plus one controlled channel. So again, the more data, the more data channels, the better.
So our PR I has 23 day two channels,
and then it also has that one controlled channel because it has so many data channels, it has that one control channel to sort of keep control of everything. Keep control of the show.
Eso again r p r I Our primary rate interface is gonna have 23 data channels, and it's gonna be used mostly for a larger organizations. But our iest bien in general, we're going to say a standard I S D in line is gonna have a max rate of 128 kilobytes per second because it has two data channels

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