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- [Instructor] 568A versus 568B.

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As we discussed previously,

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UTP, or unshielded twisted pair,

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is the favorite cable among network admins

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because of its flexibility,
easy installation, and speed.

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These cables have eight wires

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which are broken down into four pairs.

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Each pair of wires is twisted together

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across the entire length of the cable.

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Twisted pair cabling has several standards

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associated with it.

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You need to know which
wiring standard to use

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and what color sequence to work off of.

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The 568 standard is used
with twisted pair cables

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that are meant for computer
networking on the LAN,

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such as what we see here.

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We have some cables that are connected

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to the back of a patch panel,
and they're all terminated.

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All the individual wires
are terminated here.

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So we use this type of cable
for computer networking.

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This standard was developed

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by the telecommunications
industry association, or TIA,

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and adopted by ANSI.

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The 568 standard is broken
down into several substandards,

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generally speaking, the
most common standard

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or version of 568 that
you will see is 568B.

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You should memorize the
color sequence for 568B.

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And again, it's eight wires,
eight pins that we have here,

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one through eight, and
in the 568B standard,

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we have specific colors
organized in a specific sequence.

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And both ends of the cable,
both ends of a cable run

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or both ends of a patch
cable are normally gonna have

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the same sequence, the
same sequence on both ends.

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And those eight pins are white/orange.

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That means a white wire
with an orange stripe.

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The second pin is solid orange.

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The third is a white
wire with a green stripe.

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The fourth is solid blue.

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The fifth is a white
wire with a blue stripe.

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The sixth is green.

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The seventh is white with a brown stripe.

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And the eighth is brown solid.

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Now, the pins that we normally
use on ethernet networks

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are pins one, two, three, and six.

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That means we're using the
orange pair and the green pair.

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Let's take a look at the exposed wires

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of a twisted pair cable.

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So here we have a super
closeup of these wires,

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and again our eight
pins that we have here.

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And so you can see these,
you can see that it's

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a white wire with some orange stripe.

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That's the first one, white/orange.

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And then, you have that solid orange.

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That's the second pin.

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White/green, you can't
see the green stripe here,

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but it's there.

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Then, solid blue.

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White/blue, again, you can't
really see the blue stripe,

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just such a close up here.

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Solid green.

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Here, we have white/brown and solid brown.

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So those are the eight
wires and that's a close up.

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And what I did here was I cut them

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straight with a wire
cutter so that I could fit

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an RJ45 plug on them
to make a patch cable.

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Now 568A,

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568A was the version
that was originally used

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a long time ago, but the
standard changed over time.

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Today, we use the 568B version

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for most normal cable runs,

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and that means a cable
run between a patch panel

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and an RJ45 jack,

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say from a server room
to an actual workstation,

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or for patch cables.

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We'll do 568B on both ends.

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Now you might still see some 568 runs

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older networking connections,
Cat 3 cables maybe,

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so older stuff.

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But in reality, it doesn't matter too much

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from a technical standpoint.

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As long as both ends of the cable run

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are terminated with the same standard,

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you will get connectivity.

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But to pass inspection
and to meet compliance,

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you wanna be using that 568B standard.

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And look at the difference here.

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568B starts with white/orange, orange.

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568A starts with white/green, green.

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Now, why do I bring this up?

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Well, sometimes you'll need
to cross the connection.

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Sometimes you'll need
to cross the connection,

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and you do this if you
need to connect a computer

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directly to another computer,

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or if you need to connect a switch

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directly to another switch.

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So to do this, to make
this crossed connection,

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you use a crossover cable.

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The crossover cable has
one end wired to 568A

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and the other end wired to 568B,

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and it doesn't matter which is which.

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So as you can see here, pins
one and three are crossed,

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and pins two and six are
crossed, so take a look.

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On 568A, we have pin one traveling over

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to pin three on the other
end, which is wired as 568B.

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Pin two goes over to pin six.

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And then, it's reversed.

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Pin three goes over to pin one

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and pin six goes over to pin two.

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So that's the cross.
What do you need to know?

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You need to know that one
end has to be wired as 568A

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with the white/green, green,
and white/orange, orange,

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and the other end has to be 568B

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white/orange, orange,
and white/green, green.

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It's basically reversed or crossed.

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Most switches today will automatically

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cross connections as needed,

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so the crossover cable is not required

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as often as it once was.

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However, it is a tool that every PC tech

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and network admin should have available.

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But you can cross any
connection, be it a patch cable,

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a termination point at a
patch panel, and so on.

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So you might see it more
often than you would think,

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so be ready for crossed connections

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with 568A on one end, 568B on the other.

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Let's show an example of a crossover cable

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and a patch tester.

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Okay, so here we have a crossover cable,

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and I've done a closeup on this.

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And we've got two connectors.

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On this connector here,

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you can see that we have the
white/green wires or pins

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on the left side.

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And on the left side of
this other connector,

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you can see that we have the white/orange.

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So we know we're looking
at a crossover cable.

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And to test this, you can use
your trustee patch tester,

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so we'll plug that in now.

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And it doesn't really matter
which end you plug in where.

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Just make sure that both
are connected securely,

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and then you can start your test

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just by pressing the button.

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And so when we do that, we get
the cross right off the bat,

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one to three, like we mentioned before,

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and then two to six.

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Three to one, crossing the other way,

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four to four and five to five.

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Those are straight through,
they're not crossed.

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That's the blue pair.

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Six goes to two.

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And seven goes to seven,
eight goes to eight.

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Those are not crossed either.

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So we don't cross the blue
pair or the brown pair

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because generally for
ethernet connections,

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those pairs are not used.

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We use the four wires

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for a normal ethernet
networking connection,

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the orange and the green.

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And so just like we're showing here,

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we use those green pins
and those orange pins.

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Whenever we do connections,
that's normally what we use:

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pins one, two, three and six.

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So know your difference
between 568A and 568B.

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Remember that 568B is
used the most commonly

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for computer networking connections,

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but understand if you wanna
have a crossed connection

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between two computers or
between two switches sometimes,

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then one end will have to be 568A

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and the other end will be 568B.