Learn English phrases 1

quarrels, misunderstandings, and enmities
questions, disputes, and controversies
quicken, sharpen, and intensify
quiet, unaffected, and unostentatious
R
Fifteen Thousand Useful Phrases 210
raise, refine, and elevate
rapid, robust, and effective
rapt, emotional, and mystic
raptures, transports, and fancies
rash, violent, and indefinite
readiness, skill, and accuracy
reading, reflection, and observation
reaffirmed, amplified, and maintained
real, earnest, and energetic
regard, esteem, and affection
relaxation, recreation, and pleasure
religion, politics, and literature
reminiscences, associations, and impressions
remote, careless, and indifferent
reparations, restitutions, and guarantees
repress, curb, and correct
reproach, shame, and remorse
reproof, correction, and instruction
resentment, hatred, and despair
resolute, patient, and fervent
resourceful, steadfast, and skilful
respect, admiration, and homage
rest, respite, and peace
restless, discontented, and rebellious
restraint, self-denial, and austerity
reticent, restrained, and reserved
Fifteen Thousand Useful Phrases 211
reverie, contemplation, and loneliness
rich, thoughtful, and glowing
ridicule, sarcasm, and invective [invective = abusive language]
rights, powers, and privileges
rise, flourish, and decay
robustness, elasticity, and firmness
romance, adventure, and passion
rough, barren, and unsightly
rude, sulky, and overbearing
rush, roar, and shriek

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Learn English phrases

pain, toil, and privation
pale, ugly, and sinister
parable, precept, and practise
partial, false, and disastrous
passion, tenderness, and reverence
patient, gentle, and kind
peace, order, and civilization
pellucid, animated, and varied [pellucid = transparently clear]
permanent, true, and real
perplexed, tedious, and obscure
personal, sharp, and pointed
perspicuity, vivacity, and grace [perspicuity = clearness and lucidity]
pert, smirking, and conceited
pervading, searching, and saturating
petty, unsuccessful, and unamiable
Fifteen Thousand Useful Phrases 208
philosophy, morals, and discoveries
picturesque, daring, and potent
piety, charity, and humility
pillage, arson, and bloodshed
pious, patient, and trustful
pity, sympathy, and compassion
placable, reasonable, and willing [placable = easily calmed; tolerant]
place, fame, and fortune
placid, clear, and mellow
plague, pestilence, and famine
plan, purpose, and work
pleasant, friendly, and amiable
pleased, interested, and delighted
pleasure, enjoyment, and satisfaction
plenty, content, and tranquillity
plodding, sedentary, and laborious
poise, dignity, and reserve
polished, elegant, and sumptuous
politics, business, and religion
pompous, affected, and unreal
poor, miserable, and helpless
pose, gesture, and expression
powerful, dazzling, and daring
practical, visible, and tangible
precious, massive, and splendid
precise, formal, and cynical
Fifteen Thousand Useful Phrases 209
prejudice, dulness, and spite
prepossessions, opinions, and prejudices
presiding, directing, and controlling
pride, passion, and conceit
princely, picturesque, and pathetic
principles, conduct, and habits
progress, order, and happiness
prolonged, obstinate, and continued
prompt, fiery, and resolute
propriety, perspicacity, and accuracy [perspicacity = perceptive]
prosaic, dull, and unattractive
protective, propitiatory, and accommodating [propitiatory = conciliatory]
protests, criticisms, and rebukes
proud, reserved, and disagreeable
prudence, mildness, and firmness
puckered, winking, and doddering
pure, honorable, and just
purge, brace, and strengthen
purpose, intention, and meaning
puzzles, tangles, and questionings

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Cabling tools part 2

Pull String
Another way to pull cables through small spaces is with a nylon pull string (also called a fish cord),
a heavy-duty cord strong enough to pull several cables through a conduit or wall cavity. The
pull string is either put in place before all the cables are pulled, or it is run at the same time as
the cables. If it is put in place before the cables are pulled, such as when the conduit is assembled
or in a wall cavity before the drywall is up, you can pull through your first cables with
another string attached to the cables. The second string becomes the pull string for the next
bundle, and so on. For future expansion, you leave one string in with the last bundle you pull.
If the pull string is run at the same time as the cables, it can be used to pull additional cables
through the same conduit as already-installed cables.
Cable-Pulling Lubricant
It is important not to put too much stress (25 lbs of pull maximum) on network cables as they
are being pulled. To prevent stress on the cable during the pulling of a cable through a conduit,
a cable-pulling lubricant can be applied. It reduces the friction between the cable being pulled
and its surroundings and is specially formulated so as not to plug up the conduit or dissolve the
jackets of the other cables. It can be used any time cable needs to be pulled in tight quarters.
See Chapter 6 for more details, including some drawbacks of lubricant.
Labeling Materials
With the hundreds of cables that need to be pulled in large cabling installations, it makes a
great deal of sense to label both ends of each cable while it’s being pulled. That way, when it’s
time to terminate each individual cable, you will know which cable goes where, and you can
document that fact on your cabling map.
So you will need some labeling materials. The most common are the sticky numbers sold by
Panduit and other companies (check with your cabling supplier to see what it recommends).
You should pick a numbering standard, stick with it, and record all the numbered cables and
their uses in your cabling documentation. A good system is to number the first cable as 1, with
each subsequent cable the next higher number. You could also use combinations of letters and
numbers. To label the cables, stick a number on each of the cables you are pulling and stick
another of the same number on the corresponding box or spool containing the cable. When
you are finished pulling the cable, you can cut the cable and stick the number from the cable
spool onto the cut end of the cable. Voila! Both ends are numbered. Don’t forget to record on
your notepad the number of each cable and where it’s going.

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Cabling tools part 1

Hand Tools
It’s fairly obvious that a variety of hand tools are needed during the course of a cabling installation.
You will need to remove and assemble screws, hit and cut things, and perform various
types of construction and destruction tasks. Some of the hand tools you should make sure to
include in your tool kit are (but are not limited to) the following:
● Screwdrivers (Phillips, slotted, and Torx drivers)
● Cordless drill (with drill bits and screwdriver bits)
● Hammer
● Cable cutters
● Wire strippers
● Punch-down tool
● Drywall saw (hand or power)
Cable Spool Racks
It is usually inefficient to pull one cable at a time during installation. Typically, more than one
cable will be going from the cabling closet (usually the source of a cable run) to a workstation
outlet. So a cable installer will tape several cables together and pull them as one bundle.
Fish Tape
Many times, you will have to run cable into narrow conduits or narrow crawl spaces. Cables are
flexible, much like rope. Just like rope, when you try to stuff a cable into a narrow space, it simply
bunches up inside the conduit. You need a way of pulling the cable through that narrow
space or providing some rigid backbone. A fish tape is one answer. It is really nothing more than
a roll of spring steel or fiberglass with a hook on the end. A bunch of cables can be hooked and
pulled through a small area, or the cables can be taped to the fish tape and pushed through the
conduit or wall cavity.

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About cabling tools

Cabling Tools
Just like any other industry, cable installation has its own tools, some not so obvious, including
the following:
● Pen and paper
● Hand tools
● Cable spool racks
● Fish tape
● Pull string
● Cable-pulling lubricant
● Two-way radio
● Labeling materials
● Tennis ball
We’ll briefly go over how each is used during installation.
Pen and Paper
Not every cabling installer may think of pen and paper as tools, but they are. It is a good idea
to have a pen and paper handy when installing the individual cables so that you can make notes
about how particular cables are routed and installed. You should also note any problems that
occur during installation. Finally, during the testing phase (discussed later), you can record test
data in the notebook.
These notes are invaluable when it’s time to troubleshoot an installation, especially when you
have to trace a particular cable. You’ll know exactly where particular wires run and how they
were installed.

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Schedule the cable Installation

In addition to having a proper cabling design, you should also know approximately how long
the installation will take and pick the best time to do it. For example, the best time for a new
cabling installation is while the building studs are still exposed and electrical boxes can be easily
installed. From a planning standpoint, this is approximately the same time in new construction
when the electrical cabling is installed. In fact, because of the obvious connection between electrical
and telecommunications wiring, many electrical contractors are now doing low-voltage
(data) wiring so they can contract the wiring for both the electrical system and the telecommunications
system.
For a post-construction installation, you should schedule it so as to have the least impact on
the building’s occupants and on the existing network or existing building infrastructure. It also
works to schedule it in phases or sections.
Install the Cabling
Once you have a design and a proper schedule, you can proceed with the installation. We’ll
start with a discussion of the tools you will need.
See on next post

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How to install Cables

Now that we’ve covered some of the factors to take into account when designing a cabling system,
it’s time to discuss the process of installing an entire cabling system, from start to finish.
A cabling installation involves five steps:
1. Design the cabling system.
2. Schedule the installation.
3. Install the cables.
4. Terminate the cables.
5. Test the installation.
Design the Cabling System
We’ve already covered this part of the installation in detail in this chapter. However, it’s
important enough to reiterate: Following proper cabling design procedures will ensure the
success of your cabling system installation. Before you pull a single cable, you should have a detailed plan of how the installation will proceed. You should also know the scope of the
project (how many cable runs need to be made, what connections need to be made and where,
how long the project will take, and so on). Finally, you should have the design plan available to
all people involved with the installation of the cable. That list of people includes the cabling
installer, the electrical inspector, the building inspector, and the customer (even if you are the
customer). Be sure to include anyone who needs to refer to the way the cabling is being
installed. At the very least, this information should contain a blueprint of how the cables
will be installed.

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Tapping Prevention

Tapping is the interception of LAN EM signals through listening devices placed around the
cable. Some tapping devices are invasive and will actually puncture the outer jacket of a cable,
or the insulation of individual wires, and touch the metal inner conductor to intercept all signals
sent along that conductor. Of course, taps can be applied at the cross-connects if security
access to your equipment rooms and telecommunications rooms is lax.
To prevent taps, the best course of action is to install the cables in metal conduit or to use
armored cable, where practical. Grounding of the metal conduit will provide protection from
both EM and invasive taps but not from taps at the cross-connect. When not practical, otherwise
securing the cables can make tapping much more difficult. If the person trying to tap your
communications can’t get to your cables, they can’t tap them. So you must install cables in
secure locations and restrict access to them by locking the cabling closets. Remember: If you
don’t have physical security, you don’t have network security.

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How to do Fire Protection

All buildings and their contents are subject to destruction and damage if a fire occurs. The
cabling in a building is no exception. You must keep in mind a few cabling-design concerns to
prevent fire, smoke, or heat from damaging your cabling system, the premises on which they
are installed, and any occupants.Another concern is the puncturing of fire barriers. In most residential and commercial buildings,
firewalls are built specifically to stop the spread of a fire within a building. Whenever
there is an opening in a floor or ceiling that could possibly conduct fire, the opening is walled
over with fire-rated drywall to make a firewall that will prevent the spread of fire (or at least
slow it down). In commercial buildings, cinder-block walls are often erected as firewalls
between rooms.
Because firewalls prevent the spread of fire, it is important not to compromise the protection
they offer by punching holes in them for network cables. If you need to run a network cable
through a firewall, first try to find another route that won’t compromise the integrity of the
firewall. If you can’t, you must use an approved firewall penetration device
These devices form a tight seal around each cable that passes through the firewall. One type of
seal is made of material that is intumescent; that is, it expands several times its normal size when
exposed to very high heat (fire temperatures), sealing the hole in the firewall. That way, the
gases and heat from a fire won’t pass through.

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How to do Cabling Management part 2

Standoffs
When terminating UTP wires for telephone applications in a telecommunications room, you
will often see telephone wires run from a multi-pair cable to the 66-punch-down block. To be
neat, the individual conductors are run around the outside of the board that the punch-down
blocks are mounted
D-Rings
For LAN installations that use racks to hold patch panels, you need some method of keeping
the cables together and organized as they come out of the cable trays and enter the telecommunications
room to be terminated. On many racks, special metal rings called D-rings (named
after their shape) are used to keep the individual cables in bundles and keep them close to the
rackIn addition to managing cable for a cabling rack, D-rings are also used on punch-down
boards on the wall to manage cables, much in the same way standoffs are. D-rings are put in
place to support the individual cables, and the cables are run to the individual punch-down
blocks on the wall.

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How to do Cabling Management part1

Conduit
The simplest form of cable protection is a metal or plastic conduit to protect the cable as it travels
through walls and ceilings. Conduit is really nothing more than a thin-walled plastic or
metal pipe. Conduit is used in many commercial installations to contain electrical wires. When
electricians run conduit for electrical installation in a new building, they can also run additional
conduit for network wiring. Conduit is put in place, and the individual cables are run inside it.
The main advantage to conduit is that it is the simplest and most robust protection for a network
cable. Also, if you use plastic conduit, it can be a relatively cheap solution (metal conduit
is more expensive).
Cable Trays
When running cable, the cable must be supported every 48 to 60 inches when hanging horizontally.
Supporting the cable prevents it from sagging and putting stress on the conductors
inside. For this reason, special devices known as cable trays (also sometimes called ladder racks,
because of their appearance) are installed in ceilings. The horizontal cables from the telecommunications
rooms that run to the individual telecommunications outlets are usually placed
into this tray to support them as they run horizontally.

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How to do Cabling Management

Cabling management is guiding the cable to its intended destination without damaging it or its
data-carrying capabilities. Many different cabling products protect cable, make it look good,
and help you find the cables faster. They fall into three categories:
● Physical protection
● Electrical protection
● Fire protection
In this section, we will look at the various devices used to provide each level of protection and
the concepts and procedures that go along with them.
Physical Protection
Cables can be fragile—easily cut, stretched, and broken. When performing a proper cabling
installation, cables should be protected. Many items are currently used to protect cables from
damage, including the following:
● Conduit
● Cable trays
● Standoffs
● D-rings
We’ll take a brief look at each and the different ways they are used to protect cables from damage.

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About HVAC Considerations

Computer and networking equipment generates much heat. Place enough equipment in a telecommunications
room without ventilation, and the temperature will quickly rise to dangerous
levels. Just as sunstroke affects the human brain, high temperatures are the downfall of electronic
components. The room temperature should match the ambient temperature of office
space occupied by humans, and keep it at that temperature year round.
For this reason, telecommunications rooms should be sufficiently ventilated. At the very
least, some kind of fan should exchange the air in the closet. Some telecommunications rooms
are pretty good-sized rooms with their own HVAC (heating, ventilation, and air conditioning)
controls.

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what are Power Requirements

With all of these devices in the wiring closet, it stands to reason that you are going to need some
power receptacles there. Telecommunications rooms have some unique power requirements.
First of all, each of the many small electronic devices will need power, and a single-duplex outlet
will not have enough outlets. Additionally, these devices should all be on an electrical circuit dedicated
to that wiring closet and separate from the rest of the building. And, in some cases, devices
within the same room may require their own circuit, separate from other devices in that room .
The circuit should have its own isolated ground. An isolated ground in commercial wiring is a
ground wire for the particular isolated outlet that is run in the same conduit as the electricalsupply
connectors. This ground is called isolated because it is not tied into the grounding of the
conduit at all. The wire runs from the receptacle back to the point where the grounds and neutrals
are tied together in the circuit panel. You can identify isolated-ground outlets in a commercial
building because they are orange with a small green triangle on them.

The wiring closet should be equipped with a minimum of two dedicated three-wire 120-volt
AC duplex outlets, each on its own 20-amp circuit, for network and system-equipment power.
In addition, separate 120-volt AC duplex outlets should be provided as convenience outlets for
tools, test equipment, etc. Convenience outlets should be a minimum of six inches off the floor
and placed at six-foot intervals around the perimeter of the room. None of the outlets shall be
switched, i.e., controlled by a wall switch or other device that might accidentally interrupt
power to the system.

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How to do Telephone Wiring

LAN wiring components found in the telecommunications room, you will
usually also find all of the wiring for the telephone system, because the two are interrelated. In
most companies, a computer and a telephone are on every desk. Software programs are even
available that can connect the two technologies and allow you to receive all of your voicemails
as e-mails. These programs integrate with your current e-mail system to provide integrated
messaging services (a technology known as unified messaging).
The telephone cables from the individual telephones will come into the telecommunications
room in approximately the same location as the data cables. They will then be terminated in
some kind of patch panel (cross-connect). In many older installations, the individual wires will
be punched down in 66-blocks, a type of punch-down block that uses small “fingers” of metalto connect different UTP wires together. The wires on one side of the 66-block are from the
individual wires in the cables for the telephone system. Newer installations use a type of crossconnect
known as a 110-block. Although it looks different than a 66-block, it functions the
same way. Instead of using punch-down blocks, it is also possible to use the same type of patch
panel as is used for the UTP data cabling for the telephone cross-connect. As with the data
cabling, that option enhances the flexibility of your cabling system.
The wires on the other side of the block usually come from the telephone PBX. The PBX
controls all the incoming and outgoing calls as well as which pair of wires is for which telephone
extension. The PBX has connectors on the back that allow 25 telephone pairs to be connected
to a single 66-block at a time using a single 50-pin connector
The number of 66-blocks is as many as required to support the number
of cables required for the number of telephones in the telephone system.

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How to do LAN Wiring

The first item inside a telecommunications room that will draw your attention is the large bundle
of cables coming into the closet. The bundle contains the cables that run from the closet to the
individual stations and may also contain cables that run from the room to other rooms or closets
in the building. The bundle of cables is usually bound together with straps and leads the LAN
cables to a patch panel, which connects the individual wires within a particular cable to network
ports on the front of the panel. These ports can then be connected to the network equipment
(hubs, switches, routers, and so on), or two ports can be connected together with a patch cable
Some are
mounted on a wall and are known as surface-mount patch panels (also called punch-down blocks).
Others are mounted in a rack and are called rack-mount patch panels. Each type has its own benefits.
Surface-mount panels are cheaper and easier to work with, but they can’t hold as many
cables and ports. Rack-mount panels are more flexible, but they are more expensive. Surfacemount
patch panels make good choices for smaller (less than 50 drops) cabling installations.
Rack-mount patch panels make better choices for larger installations. Patch panels are the
main products used in LAN installations today because they are extremely cost effective and
allow great flexibility when connecting workstations.

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About Television

With the increase in the use of on-demand video technology, it is now commonplace to run
television cable alongside data and telephone cabling. In businesses where local cable access is
possible, television cable will be run into the building and distributed to many areas to provide
cable access. You may be wondering what cable TV has to do with business. The answer is
plenty. News, stock updates, technology access, public-access programs, and, most importantly,
Internet connections can all be delivered through television cable. Additionally, television
cable is used for security cameras in buildings.
Like telephone cable, television cables can share the wiring pathways with their data counterparts.
Television cable typically uses coaxial cable (usually RG-6/U cable) along with F-type, 75-
ohm coaxial connectors. The cables to the various outlets are run back to a central point where
they are connected to a distribution device. This device is usually an unpowered splitter, but it can
also be a powered, complex device known as a television distribution frame. Figure 12.4 shows
how a typical television cabling system might look.

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about Telephone

The oldest (and probably most common) use for a cabling system is to carry telephone signals.
In the old days, pairs of copper wires were strung throughout a building to carry the phone signal
from a central telephone closet to the individual telephone handsets. In the telephone
closet, the individual wires were brought together and mechanically and electrically connected
to all the incoming telephone lines so that the entire building was connected to the outside
world. Surprisingly, the basic layout for a telephone cabling system has changed very little. The
major difference today is that telephone systems have become digital. So most require a private
branch exchange (PBX), a special device that connects all the individual telephones together so
the telephone calls can go out over one high-speed line (called a trunk line) rather than over
multiple individual lines.
Generally speaking, today’s telephone networks are run along the same cabling paths as the
data cabling. Additionally, telephone systems use the same UTP cable that many networks
use for carrying data. They will usually share the same wiring closets with the data and television
cabling. The wires from telephone connections can be terminated almost identically
to data cabling.

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How to Selecting the Right Topology

From a practical standpoint, which topology to use has been decided for you. Because of its
clear-cut advantages, the star topology is the only recognized physical layout in ANSI/TIA/
EIA-568-B. Unless you insist that your installation defy the Standard, this will be the topology
selected by your cabling-system designer.
If you choose not to go with the star topology, the bus topology is usually the most efficient
choice if you’re creating a simple network for a handful of computers in a single room because
it is simple and easy to install. Because MACs are managed better in a star topology, a bus
topology is generally not used in a larger environment. If uptime
is your primary definition of fault resistant (that is, 99 percent uptime, or less than eight hours total downtime per year), you should seriously consider a mesh layout. However, while you are thinking about how fault tolerant a mesh network is, let the word maintenance enter your thoughts. Remember, you will
haven(n - 1)/2 connections to maintain, and this can quickly become a nightmare and exceed your
maintenance budget.
If you decide not to automatically go with a star topology and instead consider all the topologies,
be sure to keep in mind cost, ease of installation, ease of maintenance, and fault tolerance

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Ring Topology

The ring topology has a few pros but many more cons, which is why it is seldom used. On the
pro side, the ring topology is relatively easy to troubleshoot. A station will know when a cable
fault has occurred because it will stop receiving data from its upstream neighbor.
The cons are as follows:

It is expensive because multiple cables are needed for each workstation.
It is difficult to reconfigure.
It is not fault tolerant. A single cable fault can bring down the entire network.

Mesh Topology
a path exists from each station to every other station
in the network. Although not usually seen in LANs, a variation on this type of topology,
the
hybrid mesh
, is used in a limited fashion on the Internet and other WANs. Hybrid mesh
topology networks can have multiple connections between some locations, but this is done for
redundancy. Also, it is not a true mesh because there is not a connection between each and
every node; there are just a few, for backup purposes.
a mesh topology can become quite complex because wiring and
connections increase exponentially. For every
n
stations, you will have
n(n - 1)
/
2
connections. For
example, in a network of four computers, you will have
4(4 - 1)
/
2
connections, or six connections.
If your network grows to only 10 devices, you will have 45 connections to manage! Given this
impossible overhead, only small systems can be connected this way. The advantage to all the
work this topology requires is a more fail-safe or fault-tolerant
network, at least as far as cabling
is concerned. On the con side, the mesh topology is expensive and, as you have seen, quickly
becomes too complex. Today, the mesh topology is rarely used, and then only in a WAN environment
because it is fault tolerant. Computers or network devices can switch between these
multiple, redundant connections if the need arises.

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Star topology

Just as with the bus topology, the star topology has advantages and disadvantages. The increasing
popularity of the star topology is mainly due to the large number of advantages, which
include the following:
It can be reconfigured quickly.
A single cable failure won’t bring down the entire network.
It is relatively easy to troubleshoot.
It is the only recognized topology in the industry Standard, ANSI/TIA/EIA-568-B.
The disadvantages of a star topology include the following:
The total installation cost can be higher because of the larger number of cables.
It has a single point of failure, the hub.

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Cabling Topologies

The physical topology of a network describes the layout of the cables and workstations and the location of all networkcomponents. Choosing the layout of how computers will be connected in a company’s network
is critical. It is one of the first choices you will make during the design of the cabling system,
and it is an important one because it tells you how the cables are to be run during the installation.
Making a wrong decision regarding physical topology and media is costly and disruptive
because it means changing an entire installation once it is in place. The typical organization
changes the physical layout and physical media of a network only once every 5 to 10 years, so
it is important to choose a configuration that you can live with and that allows for growth.

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Disadvantages of Microwave Communications

Microwave communications are not an option for most users because of their many disadvantages.
Specifically, a few disadvantages make microwave communications viable for only a few
groups of people. Some of these disadvantages include the following:
Equipment is expensive Microwave transmission and reception equipment is the most
expensive of all the types of wireless transmission equipment discussed in this chapter. A
microwave transmitter/receiver combo can cost upwards of $5,000 in the United States—
and two transmitters are required for communications to take place. Cheaper microwave systems
are available, but their distance and features are more limited.
Line of sight required Microwave communications require a line of sight between sender
and receiver. Generally speaking, the signal can’t be bounced off any objects.
Atmospheric attenuation As with other wireless technologies (such as infrared laser),
atmospheric conditions (e.g., fog, rain, snow) can negatively affect microwave transmissions.
For example, a thunderstorm between sender and receiver can prevent reliable communication
between the two. Additionally, the higher the microwave frequency, the more susceptible
to attenuation the communication will be.
Propagation delay This is primarily a disadvantage of satellite microwave. When sending
between two terrestrial stations using a satellite as a relay station, it can take anywhere from 0.5
to 5 seconds to send from the first terrestrial station through the satellite to the second station.
Safety Because the microwave beam is very high powered, it can pose a danger to any
human or animal that comes between transmitter and receiver. Imagine putting your hand in
a microwave on low power. It may not kill you, but it will certainly not be good for you.

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What are the cat cable types

Though two cables may look identical, their supported data rates can be dramatically different.
Older UTP cables that were installed to support telephone systems may not even support
10Base-T Ethernet. The ANSI/TIA/EIA-568-B Standard helps consumers choose the right cable
(and components) for the right application. The Standard has been updated over the years and
currently defines four categories of UTP cable: Categories 3, 5, 5e, and 6. Note that Category
5 requirements have been moved to an addendum and are not officially recognized as an
approved cable for new installations. Here is a brief rundown of Categories past and present:
Category 1 (not defined by ANSI/TIA/EIA-568-B)
This type of cable usually supports frequencies
of less than 1MHz. Common applications include analog voice telephone systems. It
never existed in any version of the 568 Standard.
Category 2 (not defined by ANSI/TIA/EIA-568-B)
This cable type supports frequencies of up to
4MHz. It’s not commonly installed, except in installations that use twisted-pair ArcNet
and Apple LocalTalk networks. Its requirements are based on the original, proprietary
IBM Cabling System. It never existed in any version of the 568 Standard.
Category 3 (recognized cable type in ANSI/TIA/EIA-568-B)
This type of cable supports data rates
up to 16MHz. This cable was the most common variety of UTP for a number of years starting
in the late 1980s. Common applications include 4Mbps UTP Token Ring, 10Base-T
Ethernet, 100Base-T4, and digital and analog telephone systems. Its inclusion in the
568-B Standard is for voice applications.
Category 4 (not defined by ANSI/TIA/EIA-568-B)
Cable belonging to Category 4 was designed to
support frequencies of up to 20MHz, specifically in response to a need for a UTP solution
for 16Mbps Token Ring LANs. It was quickly replaced in the market when Category 5 was
developed, as Category 5 gives five times the bandwidth with only a small increment in
price. Category 4 was a recognized cable in the 568-A Standard, but it has been dropped
from ANSI/TIA/EIA-568-B.
Category 5 (included in ANSI/TIA/EIA-568-B for informative purposes only)
Category 5 was the most
common cable installed, until new installations began to use an enhanced version. It
may still be the cable type most in use because it was the cable of choice during the huge
infrastructure boom of the 1990s. It was designed to support frequencies of up to
100MHz. Applications include 100Base-TX, PMD (FDDI over copper), 155Mbps ATM over
UTP, and thanks to sophisticated encoding techniques, 1000Base-T Ethernet. To support
1000Base-T applications, the installed cabling system had to pass performance
tests specified by TSB-95 (TSB-95 was a Technical Service Bulletin issued in support of
ANSI/TIA/EIA-568-A, which defines additional test parameters. It is no longer a recognized
cable type per the ANSI/TIA/EIA-568-B Standard, but for historical reference purposes,
Category 5 requirements, including those taken from TSB-95, are specified in
Appendix D of 568-B.1 and Appendix N of 568-B.2.
Category 5e (recognized cable type in ANSI/TIA/EIA-568-B)
Category 5e (enhanced Category 5)
was introduced with the TIA/EIA-568-A-5 addendum of the cabling Standard. Even though
it has the same rated bandwidth as Category 5, i.e., 100MHz, additional performance criteria
and a tighter transmission test requirement make it more suitable for high-speed
applications such as Gigabit Ethernet. Applications are the same as those for Category
5 cabling. It is now the minimum recognized cable category for data transmission in
ANSI/TIA/EIA-568-B.
Category 6 (recognized cable type in ANSI/TIA/EIA-568-B)
Category 6 cabling was officially recognized
with the publication of an addition to ANSI/TIA/EIA-568-B in June 2002. In addition
to more stringent performance requirements as compared to Category 5e, it extends the
usable bandwidth to 200MHz. Its intended use is for Gigabit Ethernet and other future
high-speed transmission rates. Successful application of Category 6 cabling requires
closely matched components in all parts of the transmission channel, i.e., patch cords,
connectors, and cable.

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what are the Types of Communications Media

Four major types of communications media (cabling) are available for data networking today:
unshielded twisted pair (UTP), shielded or screened twisted pair (STP or ScTP), coaxial, and
fiber optic (FO). It is important to distinguish between backbone cables and horizontal cables.
Backbone cables connect network equipment such as servers, switches, and routers and connect
equipment rooms and communication closets. Horizontal cables run from the communication
closets to the wall outlets. For new installations, multistrand fiber-optic cable is
essentially universal as backbone cable. For the horizontal, UTP reigns supreme. Much of the
focus of this book is on UTP cable.
Twisted-Pair Cable
By far the most economical and widely installed cabling today is twisted-pair wiring. Not only
is twisted-pair wiring less expensive than other media, installation is also simpler, and the tools
required to install it are not as costly. Unshielded twisted pair (UTP) and shielded twisted pair
(STP) are the two primary varieties of twisted pair on the market today. Screened twisted pair
(ScTP) is a variant of STP.
Unshielded Twisted Pair (UTP)
Though it has been used for many years for telephone systems, unshielded twisted pair (UTP)
for LANs first became common in the late 1980s with the advent of Ethernet over twisted-pair
wiring and the 10Base-T standard. UTP is cost effective and simple to install, and its bandwidth
capabilities are continually being improved.
UTP cabling typically has only an outer covering (jacket) consisting of some type of nonconducting
material. This jacket covers one or more pairs of wire that are twisted together. In
this chapter, as well as throughout much of the rest of the book, assume unless specified otherwise
that UTP cable is a four-pair cable. Four-pair cable is the most commonly used horizontal
cable in network installations today. The characteristic impedance of UTP cable is 100
ohms plus or minus 15 percent, though 120-ohm UTP cable is sometimes used in Europe and
is allowed by the ISO/IEC 11801 cabling Standard.
This simple cable consists of a jacket that surrounds
four twisted pairs. Each wire is covered by an insulation material with good
dielectric
properties. For data cables, this means that in addition to being electrically nonconductive, it
must also have certain properties that allow good signal propagation.
UTP cabling seems to generate the lowest expectations of twisted-pair cable. Its great popularity
is mostly due to the cost and ease of installation. With every new generation of UTP
cable, network engineers think they have reached the limits of the UTP cable’s bandwidth and
capabilities. However, cable manufacturers continue to extend its capabilities. During the
development of 10Base-T and a number of pre-10Base-T proprietary UTP Ethernet systems,
critics said that UTP would never support data speeds of 10Mbps. Later, the skeptics said that
UTP would never support data rates at 100Mbps. In July 1999, the IEEE approved the
1000Base-T standard, which allows Gigabit Ethernet to run over Category 5 cable

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Need for Speed

The past few years have seen some tremendous advances not only in networking technologies
but also in the demands placed on them. In the past 20 years, we have seen the emergence of
standards for 10Mb Ethernet, 16Mb Token Ring, 100Mb FDDI, 100Mb Ethernet, 155Mb
ATM (Asynchronous Transfer Mode), 655Mb ATM, 1Gb Ethernet, 2.5Gb ATM., and 10Gb
Ethernet (over optical fiber only as of this writing). Network technology designers are already
planning technologies to support data rates of up to 100Gbps.
The average number of nodes on a network segment has decreased dramatically, while the
number of applications and the size of the data transferred has increased dramatically. Applications
are becoming more complex, and the amount of network bandwidth required by the typical
user is increasing. Is the bandwidth provided by some of the new ultra-high-speed network applications
(such as 1Gb Ethernet) required today? Maybe not to the desktop, but network backbones
already take advantage of them.
Does the fact that software applications and data are putting more and more of a demand on
the network have anything to do with data cabling? You might think that the issue is more
related to network-interface cards, hubs, switches, and routers but, as data rates increase, the
need for higher levels of performance on the cable also increases.

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why Increasing Demands of Modern Applications

A perfect example of the increasing demands put on networks by applications is a law firm
that 10 years ago was running typical office-automation software applications on its LAN. The
average document worked on was about four pages in length and 12KB in size. This firm also
used electronic mail; a typical e–mail size was no more than 500 bytes. Other applications
included dBase III and a couple small corresponding databases, a terminal-emulation application
that connected to the firm’s IBM minicomputer, and a few Lotus 1-2-3 programs. The
size of transferred data files was relatively small, and the average 10Base-T network-segment
size was about 100 nodes per segment.
Today, the same law firm is still using its 10Base-T and finding it increasingly insufficient for
their ever-growing data processing and office-automation needs. The average document
length is still around four pages but, thanks to the increasing complexity of modern wordprocessing
software and templates, the average document is nearly 50KB in size!
Even simple e–mail messages have grown in size and complexity. An average simple e–mail
message size is now about 1.5KB, and, with the new message technologies that allow the
integration of inbound/outbound faxing, an e–mail message with a six-page fax attached has
an average size of 550KB. Further, the firm integrated the voice mail system with the e–mail
system so that inbound voice mail is automatically routed to the user’s mailbox. The average
30-second voice mail message is about 150KB.
The firm also implemented an imaging system that scans and stores many documents that
previously would have taken up physical file space. Included in this imaging system are litigation
support documents, accounting information, and older client documentation. A singlepage
TIF file can vary in size (depending on the complexity of the image) from 40 to 125KB.
Additional software applications include a client/server document-management system, a client/
server accounting system, and several other networked programs that the firm only
dreamed about 10 years before. Most of the firm’s attorneys make heavy use of the Internet,
often visiting sites that provide streaming audio and video.
Today, the firm’s average switched segment size is less than 36 nodes per segment, and
the segments are switched to a 100Mbps backbone. Even with these small segment sizes,
many segments are congested. Although the firm would like to begin running 100Base-TX
Ethernet to the desktop, it is finding that its Category 3 cabling does not support 100Base-
TX networking.
When this firm installs its new cabling system to support the next-generation network applications,
you can be sure that it will want to choose the cabling infrastructure and network application
carefully to ensure that its needs for the next 10 to 15 years will be accommodated.

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What is Data cabling

                           Data cabling, It’s just wire. What is there to plan?” the newly promoted programmerturned-MIS-director commented to Jim. The MIS director had been contracted to help the company move its 750-node network to a new location. During the initial conversation, the director had a couple of other “insights”:He said that the walls were not even up in the new location, so it was too early to be talking
about data cabling.

To save money, he wanted to pull the old Category 3 cabling and move it to the new location.
(“We can run 100Base-TX on the old cable.”) He said not to worry about the voice cabling and the cabling for the photocopier tracking system; someone else would coordinate that.
Jim shouldn’t have been too surprised by the ridiculous nature of these comments. Too few
people understand the importance of a reliable, standards-based, flexible cabling system. Fewer
still understand the challenges of building a high-speed network. Some of the technical problems
associated with building a cabling system to support a high-speed network are comprehended
only by electrical engineers. And many believe that a separate type of cable should be
in the wall for each application (PCs, printers, terminals, copiers, etc.).
Data cabling has come a long way in the past 20 years.
Let we discusses some of the basics of data cabling, including topics such as:
1)The golden rules of data cabling
2)The importance of reliable cabling
3)The legacy of proprietary cabling systems
4)The increasing demands on data cabling to support higher speeds
5)Cable design and materials used to make cables
6)Types of communications media
7)Limitations that cabling imposes on higher-speed communications
8)The future of cabling performance

You are probably thinking right now that all you really want to know is how to install cable
to support a few 10Base-T workstations. Words and phrases such as
attenuation,crosstalk,twisted pair,modular connectors, and multimode optical-fiber cable
may be completely foreign toyou. Just as the world of PC LANs and WANs has its own industry buzzwords, so does thecabling business. In fact, you may hear such an endless stream of buzzwords and foreign terminology that you’ll wish you had majored in electrical engineering in college. But it’s not
really that mysterious and, armed with the background and information we’ll provide, you’ll soon be using cablespeak like a cabling professional. It is very basic for all networking.

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What are the Importance of Reliable Cabling

We cannot stress enough the importance of reliable cabling. Two recent studies vindicated our
evangelical approach to data cabling. The studies showed:
1)Data cabling typically accounts for less than 10 percent of the total cost of the network
infrastructure.
2)The life span of the typical cabling system is upwards of 16 years. Cabling is likely the second
most long-lived asset you have (the first being the shell of the building).
3)Nearly 70 percent of all network-related problems are due to poor cabling techniques and
cable-component problems.
these were facts that we already knew from our own experiences. We have spent
countless hours troubleshooting cabling systems that were nonstandard, badly designed,
poorly documented, and shoddily installed. We have seen many dollars wasted on the installation
of additional cabling and cabling infrastructure support that should have been part of the
original installation.
So give important to cabling.

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To learn how to find out the latest CCNA test information from the CISCO website

Open a browser window
Navigate to www.cisco.com. You should see something like this (remember web pages are
frequently updated so you may have to “wing it” a bit…never rely on the web to stay the
same
Next, on the left hand side you should see a link under the “Learning and Events”
link. After clicking on it then you should see
click on the link for “exam information.”
Click on the link for “Certification Exams.” It will take you to the page for current
exams and outlines (isn’t that nice?).
Click on the link for the current CCNA exam (probably the one at the top) when
this book went to print it was “640-801” and another window should open.
Again, scroll down a bit and you should see some available options (hyperlinks).
Let’s “dissect” the page a bit…some helpful links and information:
The “Preview Course Simulation Lab” link will open another page. To learn
more about the simulation tool, use the graphic tutorial links. You may want to
spend some time going through the instructions. Figure out if short-cut
keystrokes are allowed or not. Your actual CCNA exam may contain some of
these simulations.
Also look at the description of exam topics. Yeah, I know…they stink. It is kind
of getting a recipe with no name and just some of the ingredients without any sort
of instructions or amounts to use. Just make sure you feel comfortable with the
subjects. The typical Cisco test over parts 1 through 3 will also require you to
know parts 4, 5, and 6. Take that sentence for what you want. Use this to guide
your studies as you progress through your CCNA training. Not every one of
those topics is covered here in this book because this book was not designed to
replace the Cisco curriculum, but to be used to enhance and supplement it.

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setting up serial interface

Let we see how to setup serial connection between router1 and router2:
At router1:
router>enable
router#configure terminal
router(config)#hostname R1
R1(config)#interface serial0
R1(config-if)#clockrate 64000
R1(config-if)#no shut
At router2:
router>enable
router#configure terminal
router(config)#hostname R2
R2(config)#interface serial0
R2(config-if)#no shut

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