Telecommunications
Telecommunications refers to the
electronic transmission and reception of
signals for voice and data communications.
In this chapter:
• Infrastructure
• Cellular Network
Concepts > Telecommunications
• Wireless Data Communications
• Computer Network
Telecommunications
Infrastructure
In telecommunications, infrastructure
refers to the hardware, software, and
protocols that support telecommunications.
In this section:
•
•
•
•
•
Telecommunications Signals
Telecommunications Media
Radio Spectrum
Telecommunications Devices
Telecommunications Software
Concepts > Telecommunications > Telecommunications Infrastructure
Telecommunications
Telecommunications
Signals
signals are analog or digital
electronic transmissions for
the purpose of
communication.
Data transmission rate is also
referred to as the bandwidth and
is measured in bits per second
(bps). Bandwidth options fall into
two categories: narrowband or
broadband.
The terms broadband and highspeed Internet refer to a connection
that is always on or active, such as
cable and DSL.
Concepts > Telecommunications > Telecommunications Infrastructure >
Telecommunications Signals
Telecommunications Media
Telecommunications media include anything that carries a signal and
creates an interface between a sending device and a receiving device.
•Twisted pair copper cable consists of
pairs of twisted wires covered with an
insulating layer.
•A coaxial cable consists of an inner
conductor wire surrounded by insulation, a
conductive shield, and a cover.
•In contrast, fiber-optic cable, which
consists of thousands of extremely thin
strands of glass or plastic bound together
in a sheathing (a jacket), transmits signals
with light beams.
Concepts > Telecommunications >Telecommunications Infrastructure >
Telecommunications Media
Radio Spectrum
Radio spectrum, part of the
electromagnetic spectrum,
refers to all of the frequencies
available for radio waves from
about 10 KHz to 300 GHz and
their assigned uses.
All wireless
telecommunications—cell
phones, wireless Internet, AM
and FM radio—make use of
radio waves designated to
certain frequencies.
Concepts > Telecommunications > Telecommunications Infrastructure >
Radio Spectrum
Telecommunications Devices
Network devices
Hub
Switch
Repeater
Bridge
Gateway
Modem (various)
Router
Wireless access
point
Firewall
Telecommunications devices such as
routers, network adapters, Wi-Fi access
points, cellular towers, and satellites send
and receive the signals employing
telecommunications software that governs
their operations.
Point/router/switch
Satellite
Cell Tower
A modem is a device that modulates and demodulates
signals from one form to another.
Concepts > Telecommunications > Telecommunications Infrastructure > Telecommunications
Devices
Telecommunications
Software
Telecommunications
software is software based on
telecommunications protocols
used to
• control
• monitor load (amount of traffic)
• troubleshoot data
• provide security
traveling over a
telecommunications network.
Concepts > Telecommunications > Telecommunications Infrastructure >
Telecommunications Software
Telecommunications
Software
• Network operating systems (NOS)
• Network management software
– monitor the use of individual computers and shared hardware,
scan for viruses, and ensure compliance with software licenses.
• Telecommunications devices software interfaces
• Firewall software
• Standards
– Ethernet is the most widely used network standard for private
networks. This standard defines the types of network interface
cards, control devices, cables, and software required to create an
Ethernet network.
Wireless Data
Communications
Wireless data communications refers
to telecommunications that take place
over the air for data and Internet access.
In this section:
• Wi-Fi
• WiMAX
• Long Term Evolution (LTE)
• Bluetooth
• RFID
• GPS
Concepts > Telecommunications > Wireless Data Communications
Wi-Fi
Wi-Fi (wireless fidelity) is networking
technology that uses access points to
wirelessly connect users to networks within
a range of 250–1000 feet (75–300 meters).
Areas around access points where users can
connect to the Internet are called hotspots.
Positioning access points at strategic
locations throughout a building, campus, or
city, Wi-Fi users can be continuously
connected to the local area network (LAN)
and Internet, no matter where they roam on
the premises.
Concepts > Telecommunications > Wireless Data Communications > Wi-Fi
WiMAX
WiMAX is being proposed as a
solution to the “last mile” problem.
The last mile refers to the part of a
telecommunications network that
connects to residences and
businesses—the part of the network
other than the backbone.
WiMAX, which stands for Worldwide Interoperability for
Microwave Access (aka IEEE 802.16) is a so-called fourthgeneration wireless broadband technology that evolved from
Wi-Fi to provide faster Internet access at a longer range.
Concepts Telecommunications > Wireless Data Communications > WiMAX
Bluetooth
Bluetooth enables a wide
assortment of digital devices to
communicate directly with each
other (in pairs) wirelessly over short
distances.
Some Bluetooth-Enabled Devices:
•PCs
•Printers
•Keyboards and mice
•Headphones and
headsets
•Speakers
•Mobile phones
•Digital cameras
•MP3 players
•Automobiles
•Microwave ovens
•Refrigerators
•Washers and
dryers
A number of cell phone viruses have
spread through Bluetooth. An open
Bluetooth connection on a computer
can be used by a hacker to access
files on the computer. KEEP IT OFF,
WHEN NOT IN USE.
Concepts > Telecommunications > Wireless Data Communications > Bluetooth
RFID
RFID, or radio frequency
identification, uses tiny
transponders in tags that can be
attached to merchandise or other
objects and read wirelessly using
an RFID reader, typically for
inventory management to facilitate
commercial transactions.
Privacy advocates concerned that
RFID could be used by
governments and law enforcement
agencies in ways that infringe on
people’s privacy and civil liberties.
Concepts > Telecommunications > Wireless Data Communications > RFID
GPS
GPS receivers provide
navigation assistance and are
also playing a part in social
networking. Geotagging is the
process of adding geographic
identification metadata to digital
media and messages.
A GPS, or global positioning system, uses satellites to
pinpoint the location of objects on earth.
Concepts > Telecommunications > Wireless Data Communications > GPS
Pager
A pager is a small,
lightweight device that
receives signals from
transmitters for the
purpose of
communications and
messaging.
On-site paging systems are finding a
variety of uses in businesses and
organizations, including restaurants
and emergency rooms.
Concepts > Telecommunications > Cellular Network > Pager
National and regional systems set
up transmission towers, much like
cell phone networks, to cover large
geographic areas.
Computer Networks
A computer network is a
collection of computing devices
connected together to share
resources such as files,
software, processors, storage,
printers, and Internet
connections.
In this section:
• Personal Area Network (PAN)
• Home Network
Concepts > Telecommunications > Computer Network
• Local Area Network (LAN)
• Wide Area Network (WAN)
Computer Networks
• Devices attached to a network are called nodes.
Personal computers attached to a network are often
called workstations.
• Local resources are files, drives, printers or other
peripheral devices connected directly to the workstation.
Remote resources are resources that the workstation
accesses over the network.
• A system administrator is a person responsible for
setting up and maintaining the network, implementing
network policies, and assigning user access
permissions.
• Networks are classified by size in terms of the number of
users they serve and the geographic area they cover.
Personal Area network
(PAN)
A personal area
network (PAN)
typically covers a
range of around 33
feet or 10 meters.
Bluetooth technology
allows personal
devices to
communicate without
wires, sharing data,
media streams, phone
conversations, and all
types of information.
A personal area network (PAN) is the interconnection of personal
information technology devices, typically wirelessly, within the range of an
individual.
Concepts > Telecommunications > Computer Network > Personal Area
Network (PAN)
Home Network
A home network is a
local area network
designed for personal or
business use in the
home.
Home networks allow users to:
•Share a single Internet connection
•Share a single printer
•Share files
•Back up important files to another PC
•Participate in multiplayer games
•Stream music and movies from a
computer to devices around the house
Concepts > Telecommunications > Computer Network > Home Network
Local Area Network (LAN)
In an intranet, a Web server
provides confidential data to LAN
users, while keeping the data safe
from those outside the organization
through the use of a firewall.
A local area network
(LAN) is a privately
owned computer
network that connects
computers and devices
within the same
building or local
geographic area.
Concepts > Telecommunications > Computer Network > Local Area Network (LAN)
Virtual Private Network (VPN)
A virtual private network (VPN) is a
network that uses primarily public
telecommunication infrastructure, such
as the Internet, to connect an
organization’s networks dispersed
around the world into one large
intranet.
Content can be extended to specific
individuals outside the network, such
as customers, partners, or suppliers, in
an arrangement called an extranet.
VPNs typically require remote users of the network to be authenticated, and
often secure data with encryption technologies.
Concepts > Telecommunications > Computer Network > Wide Area Network
Wide Area Network (WAN)
A wide area network (WAN) connects
LANs and MANs between cities,
across a country, and around the world
using microwave and satellite
transmission or telephone lines.
A WAN that crosses an
international border is considered
a global or international network.
A LAN becomes a WAN when it
extends beyond one geographic
location to another geographic
location.
Concepts > Telecommunications > Computer Network > Wide Area Network