- [Instructor] 568A versus 568B.
As we discussed previously,
UTP, or unshielded twisted pair,
is the favorite cable among network admins
because of its flexibility, easy installation, and speed.
These cables have eight wires
which are broken down into four pairs.
Each pair of wires is twisted together
across the entire length of the cable.
Twisted pair cabling has several standards
associated with it.
You need to know which wiring standard to use
and what color sequence to work off of.
The 568 standard is used with twisted pair cables
that are meant for computer networking on the LAN,
such as what we see here.
We have some cables that are connected
to the back of a patch panel, and they're all terminated.
All the individual wires are terminated here.
So we use this type of cable for computer networking.
This standard was developed
by the telecommunications industry association, or TIA,
and adopted by ANSI.
The 568 standard is broken down into several substandards,
generally speaking, the most common standard
or version of 568 that you will see is 568B.
You should memorize the color sequence for 568B.
And again, it's eight wires, eight pins that we have here,
one through eight, and in the 568B standard,
we have specific colors organized in a specific sequence.
And both ends of the cable, both ends of a cable run
or both ends of a patch cable are normally gonna have
the same sequence, the same sequence on both ends.
And those eight pins are white/orange.
That means a white wire with an orange stripe.
The second pin is solid orange.
The third is a white wire with a green stripe.
The fourth is solid blue.
The fifth is a white wire with a blue stripe.
The sixth is green.
The seventh is white with a brown stripe.
And the eighth is brown solid.
Now, the pins that we normally use on ethernet networks
are pins one, two, three, and six.
That means we're using the orange pair and the green pair.
Let's take a look at the exposed wires
of a twisted pair cable.
So here we have a super closeup of these wires,
and again our eight pins that we have here.
And so you can see these, you can see that it's
a white wire with some orange stripe.
That's the first one, white/orange.
And then, you have that solid orange.
That's the second pin.
White/green, you can't see the green stripe here,
but it's there.
Then, solid blue.
White/blue, again, you can't really see the blue stripe,
just such a close up here.
Solid green.
Here, we have white/brown and solid brown.
So those are the eight wires and that's a close up.
And what I did here was I cut them
straight with a wire cutter so that I could fit
an RJ45 plug on them to make a patch cable.
Now 568A,
568A was the version that was originally used
a long time ago, but the standard changed over time.
Today, we use the 568B version
for most normal cable runs,
and that means a cable run between a patch panel
and an RJ45 jack,
say from a server room to an actual workstation,
or for patch cables.
We'll do 568B on both ends.
Now you might still see some 568 runs
older networking connections, Cat 3 cables maybe,
so older stuff.
But in reality, it doesn't matter too much
from a technical standpoint.
As long as both ends of the cable run
are terminated with the same standard,
you will get connectivity.
But to pass inspection and to meet compliance,
you wanna be using that 568B standard.
And look at the difference here.
568B starts with white/orange, orange.
568A starts with white/green, green.
Now, why do I bring this up?
Well, sometimes you'll need to cross the connection.
Sometimes you'll need to cross the connection,
and you do this if you need to connect a computer
directly to another computer,
or if you need to connect a switch
directly to another switch.
So to do this, to make this crossed connection,
you use a crossover cable.
The crossover cable has one end wired to 568A
and the other end wired to 568B,
and it doesn't matter which is which.
So as you can see here, pins one and three are crossed,
and pins two and six are crossed, so take a look.
On 568A, we have pin one traveling over
to pin three on the other end, which is wired as 568B.
Pin two goes over to pin six.
And then, it's reversed.
Pin three goes over to pin one
and pin six goes over to pin two.
So that's the cross. What do you need to know?
You need to know that one end has to be wired as 568A
with the white/green, green, and white/orange, orange,
and the other end has to be 568B
white/orange, orange, and white/green, green.
It's basically reversed or crossed.
Most switches today will automatically
cross connections as needed,
so the crossover cable is not required
as often as it once was.
However, it is a tool that every PC tech
and network admin should have available.
But you can cross any connection, be it a patch cable,
a termination point at a patch panel, and so on.
So you might see it more often than you would think,
so be ready for crossed connections
with 568A on one end, 568B on the other.
Let's show an example of a crossover cable
and a patch tester.
Okay, so here we have a crossover cable,
and I've done a closeup on this.
And we've got two connectors.
On this connector here,
you can see that we have the white/green wires or pins
on the left side.
And on the left side of this other connector,
you can see that we have the white/orange.
So we know we're looking at a crossover cable.
And to test this, you can use your trustee patch tester,
so we'll plug that in now.
And it doesn't really matter which end you plug in where.
Just make sure that both are connected securely,
and then you can start your test
just by pressing the button.
And so when we do that, we get the cross right off the bat,
one to three, like we mentioned before,
and then two to six.
Three to one, crossing the other way,
four to four and five to five.
Those are straight through, they're not crossed.
That's the blue pair.
Six goes to two.
And seven goes to seven, eight goes to eight.
Those are not crossed either.
So we don't cross the blue pair or the brown pair
because generally for ethernet connections,
those pairs are not used.
We use the four wires
for a normal ethernet networking connection,
the orange and the green.
And so just like we're showing here,
we use those green pins and those orange pins.
Whenever we do connections, that's normally what we use:
pins one, two, three and six.
So know your difference between 568A and 568B.
Remember that 568B is used the most commonly
for computer networking connections,
but understand if you wanna have a crossed connection
between two computers or between two switches sometimes,
then one end will have to be 568A
and the other end will be 568B.