In this lesson,
we're going to discuss the various tools we use
when working at the physical layer of our networks,
especially with copper and fiber cabling.
This includes snips and cutters, cable, strippers,
cable crimpers, cable testers, wire maps, cable certifiers,
multimeters, punch down tools, tone generators,
loopback adapters, time-domain reflectometers,
optical time-domain reflectometers,
fiber light meters, fusion splicers, TAPs,
and a spectrum analyzer.
Whew, lots of stuff we're going to cover.
All right, the first cabling tool we have
is probably the most basic one that we're going to cover,
and it's a snip or a cutter.
A snip or a cutter is used to simply cut a piece of cable
off of a larger spool or run of cable.
Now a snip looks a lot like a pair of scissors,
but it has stronger blades
because we're going to use it to cut off
twisted pair copper cables, coaxial cables,
or even larger cable bundles.
Next we have cable strippers.
Now once we cut the piece of cabling
off the larger spool using our snips,
we now need to strip off the end of the cable
and prepare it for attachment to a plastic RJ45 connector
or whatever kind of connector we're going to use.
For example, let's say I wanted to create a crossover cable.
I'm going to cut off some twisted copper from the spool.
Then I'm going to strip both ends using a cable stripper.
This allows me to remove around six to 12 inches
from the outer plastic jacket at the end of the cable.
And then I can spread out those inner wires,
prepare to attach the RJ45 connector to them,
and then I'm going to have to use a crimper to do that.
Now if I'm making a coaxial cable,
I would then use a coaxial specific wire stripper
to remove the outer jacket of the cable and the insulation,
so I can now get to that center conduit
for that RG6 connector to go through
and be put on the end of that cable.
Next we're going to use a cable crimper,
and this is how we attach the connector
to the end of the cable.
Again, let's say I'm making that crossover cable.
I need to use an RJ45 connector
and RJ45-specific cable crimper.
Normally, your cable crimper is going to be used
for twisted pair cabling
and it's going to support both RJ45 and RJ11 connectors.
If you're working with coaxial cables,
there's a different cable crimper you'll use
that'll support RJ6 or RG59 connectors.
All right, now that we've created our cable
using our snips and cutters, our cable stripper,
and our cable crimper,
we need to test the cable
and this is where we use a cable tester.
A cable tester is going to be used to verify the continuity
of each of the eight individual wires
inside of that twisted pair cable.
This will verify there's no breaks inside the cable,
and then we have good continuity from one end to the other.
By using a cable tester,
we can verify the pin outs were done properly
and that each individual wire in the twisted pair cable
is properly connected for a straight through
or crossover cable, whichever one we were making.
Now, there are different types of testers
for different types of cable.
If you're testing an ethernet cable,
you're going to need one with an RJ45 connector on the cable
and that cable tester.
Now, if you work with a lot
of different types of networks though,
you may want to use a multi-tester.
A multi-tester isn't going to support
just ethernet cables using RJ45,
but it can also support BNC connectors for coaxial cables,
IDE connectors for hard drives,
PATA and SATA connectors for internal computer devices,
RJ45, again, for your ethernet, RJ11 for your telephones,
fiber, DB25, DB9s, and anything else you might need to test.
Next, we have a wire mapping tool.
Now, a wire map tool is like a cable tester,
but it works specifically for twisted pair ethernet cables.
In addition to testing the cable from end to end,
we can diagnose any issues with that cable
such as an open pair, a shorted pair,
a short between the pairs, a reverse pair, a cross pair,
or a split pair.
Now, an open pair occurs when one or more conductors
in the pair are not connected on one of the pins
at either end of the cable.
In other words, the electrical continuity of the conductor
is being interrupted.
This can occur if the conductor
has been physically broken somewhere in the middle
or because you had an incomplete
or improper punch down on a patch panel.
Now, a short can occur when conductors of a wire pair
are connected to each other at any location
within the cable.
A short between the pairs occurs
when the conductors of two wires in different pairs
are connected at any location within the cable.
A reverse pair occurs when two wires in a single pair
are connected to the opposite pins of that pair
on the other end of the cable.
And cross pairs occur when both wires of one color pair
are connected to the pins of a different color pair
on the opposite end.
Split pairs occur when a wire from one pair
is split away from the other
and crosses over the wire into an adjacent pair.
Because this type of fault
essentially requires the same mistake
to be made at both ends of the cable,
it usually doesn't happen very often
unless somebody meant to do it.
Next we have a cable certifier.
Now, cable certifier is used with an existing cable
to determine its category or data throughput.
I can plug into your network
and find out is it a Cat5,
Cat6, Cat5e, Cat7, or Cat8 network.
It's going to tell me, based on the frequency range being used,
what the throughput of the cables are
and the standard output is shown here on the screen
as you can see.
Now, notice I have a wire mapping here
that shows my pins are correct,
that it's a straight through cable.
It's also going to tell me how long this cable is.
In this case, it knows it's 10 feet.
Then it's going to tell me what the delay is on the cable.
It tells me what the resistance is on the cable.
All that type of good information can be gotten
from a cable certifier.
Essentially, it can do a lot of the same functions
as a cable tester,
but it goes further and gives you additional details
such as length and throughput.
So I can use this to determine the length
and make sure it's right for a particular cable
or if the cable has been crimped properly
just like a cable tester does.
But all this other information is really good too.
Now, because of all this extra information,
these devices are more expensive.
When you're dealing with a simple cable tester,
you can buy that for about $10,
but a cable certifier might cost you $100 or $200 or $300.
Next, we have a multimeter.
A multimeter is a way to check the voltage or amperage
or the resistance of a copper cable.
This can be used to verify if a cable is broken or not
by checking its resistance.
Now, if I check a copper cable from end to end,
I should get something at zero resistance or zero ohms
because the center of that wire is pure copper.
Now, if there's a high level of resistance or an overload,
that means there's a break in the cable somewhere.
Now, multimeters can be used to check coaxial cables as well
to ensure there's no cuts or breaks
in the middle of a patch run.
Or it can be used to test power sources and power cords.
For example, before I plug a computer
or a switch or a router into an outlet,
I might want to check that outlet
and verify I'm getting the right voltage.
Is it getting 115 to 125 volts here in America?
That would be right.
If I'm in Europe, I should be getting 230 to 240 volts.
Either way, I can test that using my multimeter
and make sure I'm getting good, clean, reliable power
before I connect my very expensive switches, routers,
other gear into those power outlets.
Next, we have a punch down tools.
If I'm going to be using a 66 block
or a 110 block for either my phones or my networks
or even my network jacks in the wall,
I'm going to be using punch down tools to install those cables.
This is going to terminate the wire on the punch down block
and strip off the excess insulation
and trimming off all the extra wires that we no longer need.
Next, we have a tone generator, also known as a toner probe.
Now, a tone generator allows a technician
to generate a tone on one end of the connection
and use the probe to audibly detect the wire connected
on the other side.
This is often called a fox and hound
because the fox generates the tone
and then the hound is used to sniff it out
and find it using that toner probe.
A tone generator is going to be used to understand
where the cables are running inside of your walls
whenever you have an unlabeled or undocumented network
and you need to figure out which wire is connected
to which jack inside your building.
Next, we have a loopback adapter or a loopback device.
These loopback adapters are going to be different
depending on whether or not you're using ethernet
or fiber in your networks.
Now, if you're using twisted pair cabling in your networks,
you can create your own inexpensive loopback adapter
by simply connecting some of the twisted pair wires
from the transmit side to the receive pins
inside the same RJ45 connector.
Essentially, you need to have your transmit plus going
to your receive plus, which means pin one goes to pin three.
Then you need transmit minus going to receive minus.
This is pin two going to pin six.
If you're using fiber in your networks,
you can simply connect your transmit port
to your receive port using a fiber patch cable,
and this creates a loopback for you.
This is extremely easy to do if you're using an ST
or SC connection,
and they do make specialized loopback plugs
in a small form factor
so you can carry these in your pocket
when you're working as a network technician.
Now, once you connect your loopback adapter
to your network,
you can then use specialized diagnostic software
to test the connectivity of the client
and ensure everything's working properly.
Next, we have a TDR,
which is known as a time-domain reflectometer.
Now a time-domain reflectometer is going to locate breaks
in a copper cable and provide an estimate of the severity
and the distance to that break.
If I have cable running underground between two buildings
and I need to figure out where it's broken
because my network stopped working
and I need to dig a hole and fix that,
I can use a TDR to locate at exactly where that break is.
When the TDR is run,
it's going to report back that there's a break
at approximately 87 feet away,
and now I know exactly where to dig,
being able to access that cable and then patch that cable.
Now, there's also an optical version of this
called an optical time-domain reflectometer, or OTDR.
This is going to be used for fiber optic cables.
It works the same way,
but instead of using the resistance of the wire,
we're using light and the bounce back for it.
This is really helpful, especially with fiber optic cables.
'cause remember, your fiber optic cables can be many,
many miles long,
and so knowing that the break is at 3.57 miles away
is a lot more useful than trying
to figure out where it is on your own.
This is going to be essential if you're using fiber underground
and you want to make sure you have an OTDR
'cause you won't be able to visually inspect your fiber
if it's buried.
Next, we have a fiber light meter,
also known as an optical power meter.
Now, a fiber light meter is a device
that provides a continuous wave of stable source of energy
for attenuation measurements.
Essentially, this device is going to include a source
like a laser or an LED,
and it's going to be stabilized
using an automatic gain control mechanism
so it can accurately measure
how effective a fiber optic cable
is transmitting that light.
If you're using multimode fibers,
you're going to use an LED-based fiber light meter.
If you're using single mode fibers,
you need to use a laser-based fiber light meter.
Basically, you're going to connect one part
of the fiber light meter
to each end of the fiber connection.
One end is going to send light down the fiber.
The other end is going to measure how much is being received.
Then it's going to report back to you in decibels
the amount of loss experienced
as the light traveled along the cable.
If the loss is higher than 0.5 decibels,
both ends of the fiber should be cleaned, polished,
and retested once more.
Next, we have fusion splicers.
Now, a fusion splicer is a machine that's used
to permanently join two fibers together.
If you have a break in a fiber cable,
a fusion splicer is going to be used to cut out that break
and then reconnect or splice them back together again.
If you're dealing with a fiber patch cable,
I wouldn't bother using a fusion splicer.
Instead, you're just going to replace the cable.
But if you have a really long fiber cable running
between two buildings or across the city,
that is a time where it's going to be a lot cheaper
to fix that broken fiber by using a fusion splicer
than it would be to dig up
and replace the entire cable again.
Fusion splicers are going to require training
to properly use them.
It's a very specialized skillset
and a job for a network technician
who works a lot with fiber networks.
I'll tell you personally, I've never used a fusion splicer.
I've hired people when I had that need.
Next we have a TAP.
A TAP is a simple device that connects
directly to the cable infrastructure
and splits or copies those packets for use and analysis,
security, or general network management.
You're going to need to purchase and install
the appropriate TAP for your type of network
depending on if you're using copper or fiber.
Now, basically you're going to connect the TAP in line
to your network
and it's going to create a duplicate copy of every frame,
one going out the TAP port where it's going to be collected
and analyzed by your cybersecurity tool set
and the other one out to your network
so it can be processed by the equipment.
This is used heavily in cybersecurity,
but can also be used in network management
and network operations.
Finally, we have a spectrum analyzer.
A spectrum analyzer is a device that measures
and displays the signal amplitude
or the strength as it varies by frequency
within its frequency range known as the spectrum.
Now, the frequency is going to appear on the X-axis,
or the horizontal axis,
and the amplitude is going to be displayed on the Y-axis,
or the vertical axis.
A spectrum analyzer is going to be used
to measure the electrical signals
that are being passed over that medium.
Now, the medium could be a copper cable,
such as ethernet or coaxial,
or it could be a radio frequency
if you're listening to a particular radio wave.
If you're working with a satellite connection, for instance,
you might use a spectrum analyzer
to ensure your modem and radio are properly sending
and receiving the carrier waves to and from that satellite.
Again, this is a more specialized tool
than most entry-level network technicians
are not going to find themselves operating.
All right, I know that was a lot of different tools
that we just covered.
Remember, when you're dealing with the physical layer
of your network,
especially if you're dealing with copper or fiber cabling,
you're going to be using a lot of different tools
for a lot of different things.
This includes things like snips and cutters,
cable strippers, cable crimpers, cable testers,
wire maps, cable certifiers, multimeters, punch down tools,
tone generators, loopback adapters,
time-domain reflectometers,
optical time-domain reflectometers, fiber light meters,
fusion splicers, TAPs, and spectrum analyzers.
For the exam, it's important for you to understand
which tool you might use to troubleshoot
which type of cable and which type of issue.