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3 | Engineering Utilities 1 (Electrical)
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UNIT 3: BUILDING TELECOMMUNICATION SYSTEMS
1.0 Intended learning Outcome
 Identify types of transmission media.
 Name and describe standards, devices, equipment and space requirements for
a structured cabling and wireless systems.
 Interpret design and detailing information on building telecommunication
systems.
1.1 Introduction
Historical Perspective
Methods of communicating over long distances have evolved over many millennia.
Although carrier pigeons were used to convey messages from about 700 B.C.E., the
first long-distance communication systems were based on signals of sound and light
(e.g. drums and horns, smoke signals and beacon fires). Signal fires alerted the British
of the arrival of the Spanish Armada in 1588 C.E. The Chinese used rockets as signals
to warn of an imminent attack on the Great Wall. Native Americans communicated
by covering and uncovering a bonfire with a blanket to produce smoke signals or by
beating drums. The British Navy sent signals at night by raising and lowering a
lantern, which coincidentally was the same way Paul Revere was signaled with news
of the arrival of the British. In instances when clear vision was difficult (e.g., fog), bells
or whistles and fired weapons sent signals. Until almost 1800, traditional long-
distance communication was by horse-mounted dispatch riders.
In 1793 Frenchman Claude Chappe developed an optical telegraph (semaphore)
system of stations built on rooftops or towers that were visible from a great distance.
This system allowed the French to send a concise message over 100 miles (160 km) in
less than 5 min as long as visibility was good. Swede A. N. Edelcrantz developed
another type of optical telegraph system with ten collapsible iron shutters, which
when placed in various positions formed combinations of numbers that were
translated into letters, words, or phrases. Crude semaphore systems were also used in
Boston, New York City, and San Francisco at that time.
Communications by sending electrical signals over wires came only after the
demonstration of electromagnetism by Danish physicist Christian Oersted in 1820 and

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electrical flow by Michael Faraday and others before him. In 1830, American Joseph
Henry transmitted the first practical electrical signal by sending electricity through a
long set of wires to produce electromagnetism that was used to ring a bell.
American, Samuel Morse patented the first functional electrical communication
system: the electric telegraph with its system of electrical impulses identified as dots
and dashes that eventually became known as Morse Code.
Three decades later, in 1861, there were over 2000 telegraph offices in operation
across America and the East and West coasts were connected. Six years later, the first
transatlantic cable was laid, connecting England and the United States. The
telegraph flourished as a method of long-distance communication throughout the
world.
On March 10, 1876, in Boston, Massachusetts, Alexander Graham Bell invented an
electrical speech machine that transmitted voice over wires and became known as
the telephone. Bell’s assistant,
In 1895, Italian inventor Gugliemo Marconi demonstrated the first radio transmission
that was received out of a line of sight (about 2 miles) on the grounds of his family
estate in Italy. The first true radio message was sent a year later. Less than 50 years
after the telephone was invented, transatlantic communications from New York to
London became operational with signals transmitted by radio waves.
In 1865, Italian physicist Giovanni Caselli invented a pantelegraph for transmitting
pictures, the first commercial fax system. On May 19, 1924, the first transmission of
pictures over telephone wires was publicly demonstrated. On January 23, 1926, John
Logie Baird of Scotland gave the first public demonstration of a mechanical television
with images of living human faces, not just outlines or silhouettes. It was with this use
of radio waves that transmission of pictures took a major step toward the television
we use today.
1.2 Topics/Discussion (with Assessment/Activities)
1.2.1 Types of Transmission Media
The first message sent by electric telegraph
was “What hath God wrought,”
What exactly the meaning of Communication?

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Fundamentals of
Telecommunications Systems
By industry definition, telecommunication is the transmission, emission, or reception
of signs, signals, writing, images, sounds, or information of any nature by wire, radio,
optical, or other electromagnetic systems. A telecommunication system uses electricity,
light (visible and infrared), or radio waves to transmit signals that carry voice and data
transmissions.
Telecommunication systems function when a transmitter converts sound waves (e.g.,
those created when a person speaks into a telephone mouthpiece) or data into signals,
which travel along wires or through the air before reaching their destination. When a
receiver intercepts the signals, they are converted back into useful data or sound waves
that become distinguishable by the human ear and recognized by brain. A transceiver
is a telecommunications device that functions as a transmitter and receiver.
There are two types of Transmission Systems
1. Analog transmission in an electronic network is the conversion of useful sound or
data into electrical impulses. It is capable of transmitting both voice and nonvoice
messages (e.g., telex, telegrams, data). However, nonvoice transmissions are bulky
when transmitted in an analog format, so they cannot be transmitted rapidly.
2. Digital transmission in an electronic network involves a transmission of a signal
that varies in voltage to represent one of two separate states (e.g., on and off or 0
and 1). In an optical network, digital signaling can involve either pulsating (on and
off) light or a variation in the intensity of the light signal. Digital transmission over
radio systems (microwave, cellular, or satellite) can be accomplished by varying
the amplitude of the wave. Digital transmission technology offers a rapid method
of voice and nonvoice transmission.
There are many ways of communication be transmitted called media.
Transmission Media
Cable is the most common medium through which voice and data usually move from
one network device to another. It serves as the pipeline of a telecommunication
system. There are several types of cable in use, including copper wire, coaxial cable,

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and optical fibers. Copper wiring used in building telecommunication transmission is
being replaced by optical fibers because they have much greater signal capacity.
Wireless transmission capabilities are also used in buildings and are replacing the need
for hard-wired direct connections.
Connectors are the devices that connect cable to the network device (e.g., computer,
printer, entertainment center, and so forth). Connectors may come with the equipment
purchased or it may be necessary to purchase them individually. Connections on a
cable system tend to be the weakest element in any network, so they must be made
properly.
Here are the following Transmission Media:
1. Copper Wiring
Historically, copper wiring has been the principal telecommunications transmission
medium. It consists of one or more pairs of solid copper wires. Bundles of pairs of
twisted insulated copper wires form the majority of the telephone lines in the United
States and elsewhere. See Photo 1.
Figure 1. Twisted pair copper cable. (Used with permission of ABC)
Here are the standard table of twisted pair cabling.

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Table 1. ANSI/TIA/EIA STANDARD 568 CATEGORIES (CAT) OF TWISTED PAIR
CABLING.
2. Coaxial Cable
Coaxial cable has two conductors: an inner solid wire surrounded by an outer braided
metal sheath. The conductors both run concentrically along the same axis; thus the
name coaxial (COAX). Insulation separates the two concentric conductors, and a hard
casing protects the entire cable. Several coaxial cables can be arranged in bundles
protected by an outer sheathing, called a jacket.
The primary types of coaxial cabling are as follows:
Thin coaxial cable is also referred to as thinnet. Thinnet is about 1⁄4 inch (8 mm) in
diameter and is very flexible. It looks like regular TV cable. The 10Base2 designation
refers to specifications for thin coaxial cable. The 2 refers to the approximate maximum
segment length being 200 m (654 ft), but the maximum practical segment length is
actually 185 m (605 ft).
RJ45 connectors are the standard female connectors used in a telecommunication
system for UTP cable. A slot allows the RJ-45 to be inserted only one way. RJ stands
for registered jack, implying that the connector follows a standard borrowed from the
telephone industry. The RJ45 is an eight-pin connector used for data transmission or
networking and some business telephones. Pins are numbered 1 through 8 with a
locking clip at the top. Telephone connectors, referred to as RJ11 or RJ12, have four or
six pins, respectively.

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Thick coaxial cable is referred to as thicknet. 10Base5 refers to the specifications for thick
coaxial cable. The 5 refers to the maximum segment length being 500 m (1635 ft). Thick
coaxial cable has an extra protective plastic cover that helps keep moisture away from
the center conductor. This makes thick coaxial a better choice when running longer
lengths in a linear network. A disadvantage of thick coaxial is that it does not bend
easily and is difficult to install. Thicknet is not commonly used except as a backbone
within and between buildings. Triax cable is a type of coax cable with an additional
outer copper braid insulated from signal carrying conductors. It has a core conductor
and two concentric conductive shields.
Twin axial cable (Twinax) is a type of communication transmission cable consisting of
two center conductors surrounded by an insulating spacer, which in turn is
surrounded by a tubular outer conductor (usually a braid, foil, or both). The entire
assembly is then covered with an insulating and protective outer layer. It is similar to
coaxial cable except that there are two conductors at the center.
Remember!
Here are the common types of Coaxial Cable
Table 2. COMMON TYPES OF AXIAL CABLE.
3. Optical Fibers
Coaxial cable is very effective at carrying many analog
signals at high frequencies.

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Optical fibers are long, thin strands of very pure silicon glass or plastic about the
diameter of a human hair. A single optical fiber consists of three elements: a core, the
thin glass center of the fiber where the light travels; cladding, the outer material
surrounding the core that reflects the light back into the core; and a buffer coating, a
plastic coating that protects the fiber from damage and moisture. Each strand can pass
a signal in only one direction, so fiber optic cable on a network typically consists of at
least two strands: one for sending and one for receiving.
Optical fibers come in two types:
single-mode fibers that are used to transmit one signal per fiber (used in telephones and
cable TV); and multimode fibers that are used to transmit many signals per fiber (used
in computer networks, local area networks).
Take Note!
Optical fiber carries much more information than copper wire
Fiber optics refers to the technology in which communication signals in the form of
modulated light beams are transmitted over a glass fiber transmission medium.
The light in a single optical fiber travels through the core by reflecting from the mirror-
like cladding, a physical principle called total internal reflection. Light reflects from the
cladding no matter what angle the fiber itself is bent. Because the cladding does not
absorb any light from the core, the light wave can travel great distances. Light is
generated by a laser or a light-emitting diode (LED). Lasers have more power than
LEDs, but vary light output more with changes in temperature and are more
expensive.
A fiber optic relay system transmits and receives a light signal that is transmitted
through an optical fiber. An optical transmitter produces and encodes the light signal
that is sent through the optical fiber. An optical receiver that decodes the signal receives
the light signal. The receiver uses a photocell or photodiode to detect the light signal,
decodes it, and sends an electrical signal to a computer, TV, or telephone. Over long
distances, an optical regenerator is needed to boost the light signal. One or more optical
regenerators may be spliced along a long cable to amplify the degraded light signal.
Here are the common types of Ethernet Cable.
Hundreds or thousands of optical fibers
are arranged in bundles called optical
cables.

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Table 3. COMMON TYPES OF ETHERNET CABLE IN USE.
The most common wavelengths of light signals in a fiber optic system are 850 nm,
1300 nm, and 1550 nm, which are all wavelengths within the nonvisible, infrared
area of the electromagnetic light spectrum. Single-mode fibers have small cores
(about 0.00035 in or 9 _m diameter) while multimode fibers have larger cores (about
0.0025 in or 62.5 _m diameter). Optical fibers made from plastic require a much
larger core (0.04 in or 1 mm diameter) and transmit visible red light (wavelength =
650 nm) from LEDs.
4. Wireless
Wireless is a term used to describe telecommunications in which electromagnetic
waves (instead of some form of wire) carry the signal. Wireless communications can
take several forms: microwave, synchronous satellites, low-earth-orbit satellites,
cellular, and personal communications service (PCS).
Fixed wireless is the operation of wireless devices or systems in homes and offices, and
in particular, equipment connected to the Internet by the use of specialized modems.
A fixed wireless network enables users to establish and maintain a wireless connection
throughout or between buildings, without the limitations of wires or cables.
There are two types of wireless networks: peer-to-peer and access point or base
station. A peer-to-peer wireless network consists of a number of computers, each
equipped with a wireless networking interface card. Each computer can communicate
directly with all of the other wireless-enabled computers and equipment (e.g.,
printers). An access point or base station wireless network has a computer or receiver that
serves as the point at which the network is accessed. It acts like a hub, which provides
connectivity for the wireless equipment.
Two modes of transmission are used in fixed wireless systems in buildings: infrared
and radio frequency.

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On the other hand.
Wi-Fi (derived from the term wireless fidelity) is the popular expression used to
describe high-frequency wireless local area network (WLAN) technology.
1.2.2 Structured Cabling
Wiring and Cabling Standard
Prior to 1991, the manufacturers of electronics equipment controlled the specifications
of telecommunications cabling. End users were frequently confused by
manufacturers’ conflicting claims concerning transmission performance and were
forced to pay high installation and administration costs for proprietary systems. The
communications industry recognized the need to define a cost-effective, efficient
cabling system that would support the widest possible range of applications and
equipment.
Telecommunication Cabling and Pathways
Telecommunication cabling is the medium through which voice and data move from one
telecommunication device to another. Cabling physically carries electrical or optical
signals to and from devices and equipment in a telecommunication system. Cabling
media typically used include UTP and STP copper wire, coaxial cable, and optical
fibers. Wireless technology can also be used.
A pathway is a passageway, and thus a path, for cable to travel when interconnecting
devices, components, and equipment in a telecommunication system. Pathways are
typically a raceway, a channel, or trough designed to hold wires and cables (e.g.,
conduit, cable trough, cellular floor, electrical metallic tubing, sleeves, slots,
underfloor raceways, surface raceways, lighting fixture raceways, wireways,
busways, auxiliary gutters, and ventilated flexible cableways). Raceways may be
metallic or nonmetallic and may totally or partially enclose the cabling.

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TABLE 4. COMMON TYPES OF BACKBONE CABLING IN USE.
Structured Cabling Systems
A structured cabling system is the cabling, devices, and equipment that integrate the
voice, data, video, and electronic management systems of a building (e.g., safety
alarms, security access, energy management and control systems, and so on). Design
and installation of structured cabling systems adheres to national and international
standards.
In commercial buildings, structured telecommunications cabling systems include
seven subsystems. Figure 1 is a schematic of a structured telecommunications
cabling system.
These subsystems are described in the following sections.

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Figure 1. A schematic of a structured telecommunications cabling system.
Interbuilding Backbone
The interbuilding backbone is the cabling and pathways outside of the building,
including the cables carrying local exchange carrier (LEC) services (e.g., outside
telephone company), Internet service provider services, and private branch exchange
(PBX) telecommunication cable (e.g., private phone network between buildings at a
school campus or business park). Simply, the interbuilding backbone caries
telecommunication services to the building.
Building Entrance Facilities
The building entrance facility is an entrance to the building for both public and private
network service cables. It includes the cables, connecting hardware, protection
devices, and other equipment needed to connect the interbuilding backbone cabling
to the backbone cabling in the building. See Figure 2 and 3.

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Figure 2. Internet service building entrance. (Used with permission of ABC)
Figure 3. Local exchange carrier (LEC) and private branch
Exchange (PBX) building entrance. (Used with permission of ABC)
ALWAYS REMEMBER!
In buildings with a finished floor area larger than 20,000 sq. ft. (1870 sq. meter),
a secured (locked), dedicated, enclosed room is recommended for the building
entrance. An industry standard is to allow 1 sq. ft. (0.1 sq. m) of 3/4 in (20-mm)
plywood wall-mount area for each 200 sq. ft (19 sq. m) area of finished floor
area. The plywood allows mounting capabilities for equipment and panels. In
large buildings, rack-mounted and freestanding frames may also be required
to support entrance equipment within the build entrance facilities.

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Telecommunications Equipment Room
A telecommunications equipment room is a centralized space for housing main
telecommunications equipment. It is a large, dedicated, centralized room that
provides a controlled environment to house equipment, connecting hardware, splice
closures, grounding and bonding facilities, and protection apparatus.
The building entrance facilities should be located adjacent to or contained within the
equipment room to allow shared air conditioning, security, fire control, lighting, and
limited access. An industry standard is to allow 0.75 sq. ft. (0.07 sq. m) of equipment
room floor area for each 100 sq. ft. (9 sq. m) of user workstation area, or about 1 to 2
sq. ft. (0.1 to 0.2 sq. m) of equipment room floor area per workstation, with a
minimum floor area of 150 sq. ft. (14 sq. m). At least two walls should be covered
with 8 ft. (2.6 m) high, 3⁄4 in (20 mm) thick, fire-rated plywood to attach equipment.
Figure 4. Telecommunications room and equipment, including
Server, router and switches. (Used with permission of ABC)
Telecommunications Closet
A telecommunications closet is a dedicated room on each floor in a building that houses
intermediate voice and data telecommunications equipment and related cable
connections. A large building will have several telecommunications closets, and more
than one on a floor. The telecommunications closet should be located in a space that

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is central to the work areas it serves. A telecommunications closet is shown in Photo
5.
Each telecommunications closet serves as a location where junctions between the
backbone pathway and horizontal pathways are made at one or more patch panels.
A patch panel is a mounted hardware unit containing an assembly of rows of
connecting locations in a communications system, called ports. A port is receptacle
that is a specific place for physically connecting a device or piece of equipment to
another. In a network, a patch panel is located in a telecommunications closet to
serve as a type of switchboard-like device that allows network circuiting
arrangements and rearrangements by simply plugging and unplugging a patch cord.
A patch cord is a type of jumper cable that is used to create a connection from one
port in a patch panel to another port. (See Photos 6 and 7).
Figure 5. Telecommunications closet. (Used with permission
of ABC)

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Figure 6. Patch panels and patch cables. (Used with permission
of ABC)
Figure 7. Telephone patch panel and cables. (Used with permission
of ABC)
Backbone Pathway
Within a building telecommunications system, the backbone pathway connects the
entrance facilities/equipment room to the telecommunications closets for cabling that
interconnects equipment and devices in these spaces. It contains several backbone
(main) cables that carry the heaviest telecommunications traffic throughout the

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building. It is usually a vertical arrangement that connects floors in a multistory
building. However, the same function may be served by a lateral backbone for
horizontal distribution in a large building with spacious floors.
Figure 8. Wall-mounted telecommunications panels. (Used with
permission of ABC)
A building’s backbone pathway consists of the backbone cables, intermediate and
main cross-connects, mechanical terminations, and patch cords used for backbone-to-
backbone cross-connection, connections between floors (risers), and cables between
an equipment room and building cable entrance facilities.
The backbone pathway can hold any type or combination of transmission media, but
cabling typically includes UTP, STP, and optical fiber cable. Backbone cabling
distances are dependent on the type of system, data speed, and the manufacturer’s
specifications for the system electronics and the associated components used (e.g.,
adapters, line drivers, and so on). All cables in the backbone pathway are typically
strung in a star topology. This configuration allows modifications to be made without
the hassle of having to pull new cables. (See Photos 9, 10, and 11.)

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Figure 9. Horizontal backbone cabling in a wire tray. (Used with
permission of ABC)
Figure 10. Bundled horizontal backbone cabling. CAT 3 PBX
telephone cable, CAT 5e data transmission cable, interduct sheathing
containing fiberoptic cable, and two bundled interduct sheathings
containing fiberoptic cable. (From rear to front of photograph). (Used
with permission of ABC)

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Figure 12. Horizontal backbone cabling entering a firewall. The
openings are sealed with an approved firestopping material. (Used with
permission of ABC)
END OF LEARNING PACKET 3

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Work Sheet No.1
Name:____________________________________________Year& Section: ____________
College/Department:_________________________________Major Field: ____________
Direction: Answer each of following and add a piece of bond paper if necessary.
1. Describe the analog and digital transmission formats.
2. Sketch the three types of wiring topologies used in a telecommunications
network.
3. Identify and describe the types of transmission media used in a
telecommunications network.
4. Identify and describe the main subsystems of a structured cabling system for a
building telecommunications network.
5. Describe the following components:
a. Pathway
b. Drop cables
c. Patch panel
6. How does electrical equipment (e.g., motors, generators, and so on) affect
telecommunication signals?
7. How does fluorescent and HID lighting affect telecommunication signals?
8. Identify and describe the components of an advanced home wiring system.
9. Describe the types of coaxial cable.
10. Describe the function of a fiber optic system.

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1.3 References
1. Wujek J.B & Dagostino F.R. (2010). Mechanical and Electrical Systems in
Architecture, Engineering, and Construction. Pearson Education, Inc.
3. Institute of Electrical Engineers of the Philippines (2017), Philippine
Electrical Code Part 1
1.4 Acknowledgment
The images, tables, figures and information contained in this module were
taken from the references cited above.

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