Connectors - CompTIA A+ 220-1001 - 3.2

If you're connecting a
telephone or an analog modem

to your Plain Old Telephone
System, or your POTS system,

then you're probably
using this RJ11 connector.

This is what we technically call
a six-position two-conductor

connector.

That means there are six
places for wires inside

of this connector, but
we're really only using

two of those conductors.

As you can see in this cable--

that it has this RJ11
connection at the end.

You might find some
of the RJ11 cables

that you're using for your
modem or your telephone actually

have four wires inside of them
with four different conductors.

That six-position four
conductor is technically

an RJ14 connector, but it has
exactly the same connector

on the end.

And we often use these
cables interchangeably.

With a separate
set of conductors

or separate set of wires
inside of this cable,

we're able to use this
single cable for dual line

use for someone who might have
two telephones on their desk.

Here's the connection
that is inside

the modem or inside of the
device that's connecting

to this RJ11 connection.

And you can see
the two conductors

that are inside
of that connector

when you plug in the
RJ11 modular connector.

A connector that's a little bit
wider than an RJ11 is an RJ45.

This is the type of
connector you commonly

see associated with a
wired Ethernet connection.

This is an eight-position
eight-conductor connection,

which means we have all eight of
those connectors and all eight

of those wires that are being
used inside of that cable.

This is also similar
to a format you

might see called an RJ48C,
which has an eight-position four

conductor.

Those are commonly seen
with T1 or wide area network

connections.

An RS-232 connection stands
for Recommended Standard 232.

This is a serial connection
type that has literally

been around since 1969.

And it has been around
so long because it's

able to connect to so many
different kinds of devices.

Before there was
USB-type connectivity,

we commonly used RS-232
to connect our mouse

connections, our printers, our
networks, and other devices

as well.

These days, RS-232
is commonly used

as a configuration
port on a switch

or a router or a
firewall, and it's

plugging into a serial
interface on a laptop

or another computer.

The 25-pin version of RS-232 is
usually referred to as a DB25.

This nine-pin connection,
which is a bit more modern,

you'll sometimes hear
referred to as a DB9.

But, technically,
it's the smaller style

of D-subminiature interface,
which is the E side.

So you may see this
nine-pin connection being

referred to as DB9 or DE9.

It's really referring to
exactly the same connection.

A very common type of
coaxial cable connection

is a BNC connection.

The B in BNC stands
for Bayonet, which

is the style of cable that plugs
in and then twists to lock.

And you can see the locking
mechanism on the cable

right here.

The N and the C in BNC
stands for Paul Neill,

who is at Bell Labs, and Carl
Concelman, who is at Amphenol.

They designed this
particular connection

and called it the
BNC connection.

As I mentioned, this
is commonly seen

on coax connections for wide
area networks, especially

DS3-type WAN links.

Because this BNC connection
is connecting coax together,

you're usually working
with a type of media that's

a little more bulky and
a little more rigid,

and it can be more
difficult to work with.

But because you're using this
bayonet-type connection that

twists in and
locks in place, you

can be sure that nobody
can accidentally pull out

one of these connections
because you must untwist this

a quarter of the way before
you're able to pull it out

of that connection.

Another type of connector that
does not come disconnected

very easily is an F connection.

It's commonly used
on cable television

or cable-modem-type connections.

You can see that the
connection itself is threaded.

So to plug in this coax
connection, which is commonly

RG6 or RG59, you are threading
this onto the connection.

So this makes it very difficult
to accidentally disconnect an F

connection because
you first must

untwist all of those
threads before the cable can

be removed.

USB is some of the most common
connectors we use these days.

And for USB 1.1 and 2.0, we
use this style of connector.

The standard A plug has
the same form factor

as other USB standards,
although there

may be a different number
of pins inside of a USB 1.1

or USB 2.0 plug.

The standard B plug for
these versions of USB

is this squared-type plug.

And this is usually
one that you would

plug into a printer or
some other peripheral.

For smaller mobile
devices, you commonly

see the mini B plug
or the micro B plug

being used for
USB-type connections.

The USB 3.0 and
higher connections

have similar but slightly
different types of connectors.

The USB 3.0 standard
B plug, you can see,

still maintains
that square shape,

but there's additional
areas on the top

of that particular plug.

The standard A plug
looks and feels

exactly the same as the older
versions, but, as I mentioned,

this version has some
additional pins on the inside.

And you can see the micro B
plug has changed quite a bit.

We have some
additional pins that

have been added on if
you're using this newer

style of USB micro B.

A newer standard connector for
USB is the USB-C connector.

You can see these are relatively
small interfaces, as you

can see by the side
of this laptop,

and the USB interface
doesn't have a top or bottom.

You can plug it in
either way, and it

works exactly the
same regardless

of how you connect it.

If you're using a mobile
device from Apple,

you may be using a
Lightning connector.

This is a proprietary
Apple connector

that has eight different
pins that you would use

to connect your mobile device.

This has a number of
advantages over the Micro-USB

that you might find on
other mobile devices.

One advantage is that it
has a higher power output,

so you can charge those
mobile devices even faster.

Just like USB-C, the
Lightning connector also

does not have a top or bottom.

So you can simply
plug it in, and it's

going to work either way.

This is also a simpler
design than Micro-USB,

and it's designed to be more
durable than those connectors

as well.

In an earlier video, we looked
at all of the different SCSI

interfaces that
you might run into.

And in the older
legacy style of SCSI,

you can certainly
connect to those devices

using many, many different
types of interfaces.

Here's an example
of a 68-pin legacy

SCSI connection that's
on a motherboard.

And you can see the
difference between a SATA

drive and those connections, the
PATA drive and the very large

PATA data connection, and
then the SCSI connection

on the drive at the bottom.

Modern SCSI drives use a serial
attached SCSI drive connection

very similar to the
SATA-type connections

you would see on those drives,
although these interfaces

are slightly different than the
SATA drive that you might see.

And if you have internal
serial attached SCSI devices,

you may have an internal
high-density connector

such as this one that might be
used for those serial attached

SCSI drives.

If you're plugging in an
external device with SATA,

you're probably using
an eSATA connection.

An eSATA connector has ears on
the side and a single square

that's in the middle
of the connector.

This is a little different
than the internal SATA-type

connection that you would have
inside of a computer, where

the inside is more
of an L shape,

and there's a single ear
that's along the outside.

On the inside of our
desktop computers,

we may be connecting
older peripherals

or maybe connecting
our fans to something

like these four-pin
Molex connectors.

We call this a Molex connector
because it was created

by the Molex Connector Company.

Technically, this is also
an AMP MATE-N-LOK connector,

and it provides 12-volt
and 5-volt power

for these internal peripherals.

So if you're connecting
older storage

drives or the internal fans
or other components inside

of your system, you might be
using this Molex connector

to provide that power.

The power for Molex is
usually provided directly

from the power supply.

This power supply is
a bundle of cables

with other connectors on
the end for connection

to the motherboard, and you
can see the four-pin Molex

connectors are there as well.