INTERNETWORKING I

CHAPTER 9 STUDY GUIDE

 

 

What is the first thing (safety-wise) you should do when working in ceilings, walls, or attics?

 

Turn off all power.

 

What are some of the precautions you should take when working with electrical devices?

 

Never work on a device when it’s plugged in

Test outlets with a multimeter

Locate all electrical condiuts and power wires before installing cable

Property ground all equipment

Never cut or nick a live 120 AC line

Don’t touch live wires!

 

What are some of the general safety precautions you should take when installing cable?

 

Wear safety glasses

Measure carefully (measure twice, cut once)

Know where electric wires are in the wall where you will be drilling/cutting

Keep dust down (it can start a fire)

Make sure you have your ladder placed correctly

Don’t wear baggy clothes; wear long sleeves and pants to protect your arms and legs

Know where the fire extinguishers are located

If working in a dropped ceiling, survey the area first. Know what’s already in the ceiling.

Consult with the building engineer/maintenance personnel for special hazards (asbestos, lead, PCB’s, etc.)

Pick up your tools so no one (including you!) stumbles over them

 

What is the connector you must use for CAT 5 cable?

 

RJ-45

 

What are the steps you go through to surface mount a telecommunication box?

 

1.                  Select the RJ-45 jack location

2.                  Run the wire to the location, either inside or outside the wall

3.                  Mount the box with adhesive or screws

4.                  Feed the wire into the top or rear of the box

5.                  Punch the wire down into the RJ-45 jack

6.                  Insert the RJ-45 jack into the box

7.                  Attach the faceplate to the box

8.                  Label the box

 

What are some of the factors you should take into consideration when flush mounting a telecommunication box?

 

What type of material is the wall made from?

Do you want to mount boxes on wide wood baseboards?

Decide if you’re going to use a box or a low-voltage mounting bracket

Why shouldn’t you try to flush mount a box within 5 cm. of the bottom of a wall?

 

Because you’ll run into the bottom plate of the wall and you won’t be able to get the box flush.

 

What is the term we use to indicate the process of matching wires of a cable to the proper terminals on the telecommunication jack?

 

sequencing

 

Why is this important?

 

If the wires aren’t in the right sequence, you’re circuits may not work. If your circuits aren’t right, your network won’t perform properly.

 

What wires are used to create the two circuits in CAT 5 cable when wiring an RJ-45 or patch panel?

 

1,3 / 3,1       2,6 / 6,2

 

What is the tool called that is used to insert the cable wires into a patch panel? How is it used?

 

punch down tool / punch tool

 

Name at least 6 do’s and dont’s of stringing cable.

 

DO

DON’T

use cable ties

untwist more than 1.2 cm or cable for connections

leave slack

Minimize bend radii (<90 degrees)

leave service coils

No kinks

use support bars

stretch cable to “make it fit”

use cable management panels

use staple guns to attach cable

use velcro ties

string network cable in the same raceway as electrical wires

 

 

What is a cut sheet?

 

A rough diagram that shows the locations of cable runs in a building

 

Where should labels be attached in a LAN?

 

·        on both ends of the cable

·        on the faceplates of telecommunication boxes

·        on workstation patch cords

·        on cable connections at patch panels

 

Name at least 4 do’s and don’ts of stringing cable from multiple spools.

 

DO

DON’T

assign a letter to each box for identification purposes

uncoil cable from boxes (leave in the box)

tie cables together with electrical tape

cut cables unless they have a label on them

bind cable ends together with a pull string

 

allow enough slack to reach to the floor and extend another 50-90 cm. (service coil)

 

cut wire with wire cutters to get a clean cut (better signal)

 

 

Name at least three ways to wall-mount UTP CAT 5. Explain what each one is.

 

tie wraps – a wrap that allows you to tie the cables together and mount on a wall

decorative raceway – wall-mounted channel with a removable cover that presents a finished apearance

gutter – same as decorative raceway but unfinished. Usually used where it won’t be seen (attics, dropped ceilings)

 

When must you use fire-rated cable?

 

when cable is run where air is circulated.

 

What is a telepole?

 

A telescoping pole with a hook at one end to hold the cable.

 

What is fish tape?

 

String or tape you use to “fish” (pull) cable through a ceiling or wall.

 

 

What is the definition of a wiring closet? Name some of the items you might find in one.

 

the central junction point for the wiring and wiring equipment used to connect devices in a LAN.

 

patch panels, hubs, routers, switches, bridges

 

What is the difference between an IDF and a MDF?

 

The MDF is the main wiring closet in the building. It is where all the other wiring closets come together. It is usually positioned as close to the POP as possible.

 

The IDF is an intermediate wiring closet (one on another floor or another catchment area on the same floor if it’s a really big building). IDF’s are dependent on the MDF.

 

Together, MDF and IDFs make an extended star physical topology.

 

How many pins are on a patch panel (where you would wire in one cable)?

 

8

 

Is the color-coding on punch down blocks important? Why or why not?

 

Yes. If you don’t get the right wires in the right pin location, your circuits might not work. If your circuits don’t work, your LAN won’t work.

 

Name the 8 steps in testing a network:

 

1. Divide the network into smaller logical units

2. Test each unit, one section at a time

3. Make a list of any problems you find

4. Use the list to try to find any malfunctioning network element(s)

5. Replace any bad elements, one at a time

6. Test with each new element. Keep testing until you find the problem.

7. Repair the bad element.

8. Replace the bad element if you can’t repair it.

 

Why is it necessary to do a baseline test? What is it used for?

 

It gives you a clear picture of what the network should look like when it’s operating properly. You can use this as a baseline to compare your network on an on-going basis. It can help you trouble shoot problems in the future.

 

 

 

What is a cable tester used for? What is another name for a cable tester? Name at least 5 things it can test for.

 

It is a hand-held device that can certify that cable meets the required IEEE and TIA/EIA standards.

It is sometimes called a time domain reflectometer (TDR)

·        to determine cable distances (runs)

·        locate bad connections

·        provide wire maps

·        measure signal attenuation

·        measure near-end crosstalk (NEXT)

·        detect crossed pairs

·        perform noise level tests

·        trace cable behind walls

 

How do cable testers work to find a shorted cable?

 

they send an electrical impulse through the cable and then time the signal’s reflection from the end back to the tester.

 

What is a crossed pair?

 

When wires that make a circuit in CAT 5 cable are crossed in their pins (either in an RJ-45 jack or patch panel) (e.g., instead of 1-3, it’s wired 1-2)

 

What is a split pair?

 

When wires that make a circuit in CAT 5 cable are split between the pins (e.g., instead of 1-3, it’s wired 3-3).

 

Name at least 6 things that can add noise to a copper cable.

 

fluorescent lights

heaters

radios

air cleaners

televisions

computers

motion sensors

radar

motors

switches

welders

auto ignitions

electronic devices of all kinds