Transcript CHAPTER 3 Telecommunication and Network

CHAPTER 3
Telecommunication and
Network
Presented by:
ARLENE N. BARATANG
Definition of Terms
• Communication is simply the
process of sending and receiving
data and information.
• Computer communication is a
process in which one computer
sends or transfers data,
instructions, and information to
another computer.
Definition of Terms
• Telecommunication. The process
of transmitting and receiving of
voice, video, or computer data in a
form that could be send and/or
receive by the different
communication devices over a
long distance channel
Communication
Devices
Communication devices
• Communication devices are
types of hardware capable of
sending data, instruction, or
information between a transmitting
devices and receiving devices.
Communication devices:
•
•
•
•
•
Sending device or terminal
Communication device
Communication channels
Communication device
Receiving devices or host
computers
Modems
• Modem stands for modulate and
demodulate is used for data
conversion
• Modulator is used to changed
digital to analog; and demodulator
is used to convert analog signal to
digital signal.
Types of Modems:
• Internal modem is a separate card
that is use to be inserted into an
expansion slot of the mainboard of
the computer.
• External modem is a separate
device that is used to plug into a
special port (RS-232) on a
computer with the telephone line
connected to a telephone outlet.
• Wireless modems are for mobile
users that allow access to the web
or network without telephone wire
connection.
ISDN and DSL Modem
• the same telephone line can carry
more signals using the technique
of multiplexing.
• Integrated Services Digital
Network (ISDN) is a set of
standard for digital transmission of
data over standard copper
telephone line allowing one
telephone line to be used for
transmission of three or more
signals at once.
• Digital subscriber line (DSL) is
another digital line that transmits
signals at a faster rate on existing
standard telephone lines. This can
be used for both voice and data
signals.
Cable Modem
• Cable modem or broadband
modem sends and receives
signals over the cable television
network to subscriber’s home
providing faster Internet
connections than dial-up and ISDN
modems.
Network Interface Card
• Network Interface Card is a
printed circuit board (PCB) or card
that is inserted to an expansion
slot of the motherboard of the
computer.
Communication
Channels
• Channel is an essential aspect in data
communications. This serves as the
pathway for communicating devices to
send and receive data and information.
Communication
channel
have
bandwidth. This is the breadth of the
channels where the signal travels. The
higher the bandwidth, the more data or
information can be transmitted through
the channel.
TRANSMISSION MEDIA
• Transmission media are made up of
different materials or techniques capable
of carrying one or more signals for
transmission.
• When a transmission media can transmit
only one signal at a time, it is called
Baseband. But when a media can
transmit multiple signals simultaneously,
this refers to as Broadband. DSL,
CATV, and satellite offer broadband
transmission.
Two types of
transmission media
• Physical transmission media or wired
transmission media use insulated wire,
cable, fiber optics, or other materials for
transmitting communication signals.
• Wireless transmission media uses air
or space for sending communication
signals through electromagnetic wave or
infrared signals.
Types of Physical
Transmission Media
• Twisted-pair cable
is a transmission
medium consisting
of one or more
insulated twistedpair of wire bundled
together as one
cable.
Types of Physical
Transmission Media
• Coaxial cable is a shielded high frequency
transmission medium consisting of a single
copper wire surrounded by insulating materials,
woven or braided metal, and plastic outer
covering.
Types of Physical
Transmission Media
• Fiber optic cable is insulated thin
strand of glass or plastic (2/1000 of an
inch) where signals converted to light
fires by laser burst pass through.
Types of Wireless
Communication Media
• Communication Satellite is a space station
22,300 miles above the earth’s equator. This
receives microwave signals from earth-based
station, amplifying the signals and transmitting it
back over a wide area to any number of earthbased stations as fast as 50 Mbps. The
transmission of signal from earth-based station
to space satellite is called uplink. And the
transmission of signal from space satellite to
earth-based station is called downlink.
Uplink and downlink
transmission of signal via
Communication Satellite
• Microwave radio transmission involves
transmitting of electromagnetic signals
from one microwave station to another at
a rate of 45 Mbps. Microwave stations
are earth-based stations that have a
reflective disc containing antenna,
transceiver, and other equipment used in
line-of-sight transmission of signals.
Electromagnetic signals transmitted
via Microwave stations
• Broadcast
radio is a wireless
transmission that involves sending or
distributing of signals through the air
either over short distance or long
distance. Radio transmission requires a
transmitter and receiver to transmit and
receives radio signals. The receiver of
the broadcast signal must have an
antenna located within the range of
signals being transmitted.
Broadcast Radio
transmission
• Bluetooth is a technology that
uses short range radio wave
transmission among other users
using Bluetooth enabled-device. It
has a small chip that allows it to
communicate with other Bluetooth
enabled devices.
Short range radio wave
transmitted using Bluetooth
• Infrared (IR) is similar to
microwave radio that needs no
obstruction on the line of its signal
transmission.
Infrared is a
transmission media that transmit
signals using infrared light waves
at the speed of 1 to 4 Mbps.
• Cellular radio is a form broadcast radio that is
widely used for mobile communication like the
cellular telephone and wireless modem. The data
transfer rate for cellular radio ranges from 9,600
bps to 14.4 Kbps.
Cellular phone
signals travel on
different
channels
• Personal communication services
is a set of technologies for digital
cellular devices that have voice mail,
call forwarding, fax capability, and
caller ID. These devices also have
wireless modems allowing Internet
access and e-mail capabilities. Among
these
devices
are:
handheld
computers, cellular phone, pages, and
fax machine.
NETWORK
• A Network consists of two or more
computer
system
connected
by
communications channel that facilitates
among users to allow sharing other
resources with other users. Computer
network may span over a specific
geographic area and linked to each
other using cables, telephone wires,
radio waves, satellite, or infrared light
beams.
Advantages of Using a
Network
•
•
•
•
Facilitating communication
Sharing hardware
Sharing data and information
Sharing software
Types of Computer
Network
  Local Area Network (LAN) is a
network that in confined in limited
geographic area connecting computers
like in a building or one establishment.
  Wide Area Network (WAN) is a
network of computers that covers a
large geographic area as in a
metropolis or city. Computers are
connected farther apart and are
connected by telephone lines or radio
waves.
  Metropolitan Area Network (MAN) is a
backbone network designed connecting
local area network in a metropolitan area,
town or city. This typically includes one or
more LANs but covers a smaller
geographic area than WAN.
  Campus-Area Network (CAN) is
designed within a limited area, such as
military base and school campus.
  Home-Area Network (HAN) is network
contain within a user’s home connecting
different home digital devices.
NETWORK TOPOLOGIES
• Topology
refers
to
the
configuration layout, or physical
arrangement of connected devices
on a communication network.
Basic Type of Network Topologies
• Bus Network consists of a single central cable
wherein the computers and other devices are
connected. The backbone is the physical cable
that connects the computers and other devices.
Bus network is very popular in LANs because it
is inexpensive and easy to install.
Computer devices
connected in a bus
network shares a
single path
• Ring Network is network layout connecting
computers and devices in a closed loop. Data
transmission in a ring network travels from one
device to another around the entire loop, in one
direction. In ring topology two cable paths exist,
messages can only travel in one direction.
Computer
devices
connected in
a continuous
loop
• Star Network of computers and devices
connected to a central computer forming
a star. The central computer, called hub,
serves a common connection points for
transmitting and sending data to some
other devices connected to the network.
A star network
contains
a
centralized
host computer
• Tree topology is a configuration that
incorporates multiple star connections onto
a bus topology. This bus/star layout
supports future expansion of the network
better than a bus due to limitation of
number of devices due to the broadcast
traffic it generates or a star topology with
limitation due to the numbers of hub ports
alone.
• Mesh topology is configuration topology
that involves the concept of routes where
messages sent took any several possible
paths from the source to its destinations.
INTERNET and WORLD WIDE
WEB (WWW)
• Internet is a worldwide network of
interconnected computers that transmit data or
information using the standard protocol. It
interconnects large and small networks around
the world including domestic, academic,
business, and government network, which
may have various information and services like
e-mail, voice mail, newsgroup, video
conferencing, instant messaging, facsimile,
online chatting, file transfer, and other
interlinked web pages and other documents of
the World Wide Web.
• World-Wide Web, also called the
Web, WWW, and W3, is information
space
on
the
Internet
where
hypermedia documents are stored and
can be retrieved by means of a unique
addressing scheme. This is one of
many services available on the Internet
that provides
Worldwide collections of electronic
document called Web page presented
in text, graphic, audio, and video called
Hypermedia.
The Internet and World Wide Web
INTRANET and EXTRANET
• An Intranet is a private internal
network
that
applies
Internet
technologies such as Internet protocol,
network connectivity, and even public
telecommunication system to securely
share information among other users
of the organizations. Intranet is a
small version of Internet that exists
within an organization or company.
Some of the applications of
Intranet
  Electronic publishing of organizational
materials like telephone directories, event
calendar, procedure manual, job posting,
and employee benefits information.
  Groupware application like project
management, chat rooms, news groups,
group
scheduling,
and
video
conferencing
• Extranet is similar to a private
Internet over the Internet. This
could be viewed as part of the
organization’s Intranet that is
extended among other users
outside the organization. Extranet
allows customer or suppliers to
access part of the organization’
Intranet.
Advantages of Extranet
1.
2.
3.
4.
Improve employee productivity by automating
processes in reordering of inventory from
suppliers.
Allows organization or porject information to
be viewed on-line at time convinient for other
authorized users outside the organization
Immediate access to the most updated
information of the organization by authorized
users
Can
improve
relationships
with
key
customers, providing them with accurate and
updated information
Disadvantages of Intranet
1. Can be expensive to implement and
maintain within an organisation (eg:
hardware,
software,
employee
training costs
2. Security can be a big concern when
dealing with valuable information
3. Can reduce personal contact with
customers and business partners
which may affect loyalty.
SEARCHING for
INFORMATION on the
WEB
• Web browser is a software or program
that allows the user to access Web
pages. This is a software system that
enables the users to retrieve
hypermedia by typing in search
parameters or clicking on a graphic.
Microsoft Internet Explorer and
Netscape are examples of Web
browser for personal computers.
• Web site is a collection of related
Web pages that refer to a computer
linked to the Internet containing
hypermedia that can be accessed
from any other computer in the
network by means of hypertext links.
• Home page refers to the first page
of any Web site that provides
information
about
the sites
purpose and content. It is similar
to a table of content of a book
showing what is contains inside.
• Search engine is a software program
that that the computer user launches to
search for a Web site, Web pages, and
Internet files.
This software assist
computer users in locating Web pages
on certain topics or in locating specific
pages for which the Web address is not
known to the users. This unique
address is called Uniform Resource
Locator (URL).
Uniform Resource
Locator instructs the browser where to
locate the document.
Three Parts of URL
• PROTOCOL – set of standards that govern the
communication of data. HTTP is the protocol
for hypertext and the letters stand for Hypertext
Transport Protocol.
• DOMAIN NAME – is the address of the Web
Site where the Web Page is stored. The name
can contain periods (called dots).
• Path can identify a certain accounts at the Web
site and the hypertext markup language
(HTML) is the program code that creates the
hypertext links, and it is entered in lower-case
letters.
Parts of URL
• When the correct URL is entered in the
browser, it sends a request to the Web
server that store the Web site being
requested.
The Web server then
retrieves and delivers the Web page to
the browser of the requesting computer
user.
Google-based search
engines
•
•
•
•
AOL Search
ICQ
Netscape
GahooYoogle
Type of Web Pages
• Advocacy contains content that
describes a cause, opinion, or idea that
convince the reader of the validity of the
cause, opinion, or idea.
www.greenpeace.org
• Business/Marketing contains
content that promotes or sells
products or services.
www.disney.go.com/park3
• Informational web page contains
factual information.
www.census.gov.ph
• News web page contains newsworthy
materials including stories & articles
relating to current events, life, money,
sports, & weather.
www.esp.gov.com
• Portal offers a variety of Internet
services from a single, convenient
location.
Examples: yahoo.com, AOL,
Altavista
• Personal web page is a web page
that contains variety of general
uses such as job hunting.
www.rweddingsite.com
WEB PROGRAMMING
LANGUAGES
• Web server scripting languages.
Examples: Perl, PHP, ASP, JSP
• Operating systems. Examples: Unix
FreeBSD, Red Hat Linux, Windows
9x/2000/XP
• Web client languages. Examples:
HTML, Java-script, VisualBasic scripts,
Java applets, Macromedia Flash Action
Script
WEB PROGRAMMING
LANGUAGES
• Database products. Examples: MySQL,
PostgreSQL, MS SQL, Sybase ASA Server.
• Programming languages. Examples: C/C++,
Java, Delphi, Microsoft C#, Microsoft .NET
framework, Windows technologies: MFC,
COM, ATL, ActiveX.
• Database programming technologies.
Examples: DAO, ADO, ODBC, JDBC, SQL
• Software development under Windows.
Examples: Visual C++, using MFC, COM,
DCOM, ATL, ActiveX technologies; under
Unix/Windows in Java, Delphi, Kylix
INTERNET and
TELECOMMUNICATION
SERVICES
• E-mail (Electronic Mail) is the
exchange of text messages,
letters, memos, report, and
computer files transmitted via
communication network such as
Local Area Network (LAN) and
Internet. Internet e-mail address
consists of local part and a host
part.
Parts of Internet e-mail address
• Video conferencing is another use of
communication technologies that
involves using video to conduct a
meeting between two or more
participants located at geographically
disperse region. Video conferencing
permits participants of the meeting to
partake as if they were in the same
conference room. Video conferencing
requires computer with microphones,
speakers, video cameras, and
communication devices and software.
• Cell phones were first introduced for
voice call and sending and/or receiving
text messages. Recent models of these
cell phones even integrate the
capabilities of connecting to the
Internet allowing users to search for
information, buy products online, and
even chat with businesses and friends
around the world. Users can also send
messages, pictures, video and audio
over cell phone using multimedia
messaging services (MMS).
• Handheld computer can also be
connected to the Internet using
telephone lines or wireless
connection, like Wi-Fi. After
connecting these device users
can have a full access to the
Internet and all its applications
• Job search and career information
services are available for job hunters
using the Internet and the Web. Some of
the job search sites where job hunters
may visit are: HotJobs.com, Job.com,
Monster.com, JobCentral.com,
CollegeRecruiter.com,
CareerBuilder.com, Career.com,
TrueCareers.com, JobStreet.com, and
JobsDB.com.
• Instant Messaging, or IM, is a
synchronous or real-time Internet
communication
service
that
notifies the user where one or
more communicating users are
on-line. This notification allows
the exchange of messages on
real-time.
• Chat rooms allow the users to
communicate in real-time with
each other over the computer
connected to the Internet. As the
sender type the message on the
keyboard, other users connected
to the same chat room server can
see what you type.
• Global Positioning System
(GPS) Services, is consists of
one or more earth-based
receivers that accept and analyze
signals transmitted by satellites in
order to determine the geographic
location of the receiver.
• Groupware is a workgroup
computing which includes network
hardware and software that
enable the members of the group
to communicate, schedule
meetings, manage projects, and
make group decisions.
• Newsgroup is an area on the Web
wherein the users conduct written
discussion about a particular subject
or topic. Newsgroup is also called
threaded discussion. Newsgroup
is synchronous communication that
differs with chat room. Chat room is
asynchronous
type
of
communication.
• Fax machine (fax) is used to
send or receive documents,
illustrations, photographs, and
other graphics. This allows the
users to store received faxes in
the computer that could be later
use in e-mail program for other
recipient or users.
• Internet telephone enables the users to
converse over the Internet. This is
different with telephone that uses Public
Switched Telephone Network (PSTN) to
connect to a calling party. To talk with
other users on-line through Internet
telephone, users need have Internet
Telephone Software and a sound card
that will digitize and compress any
conversations before transmitting it over
the Internet.
• A new technology that allows the users
to make a telephone call using the
broadband Internet connection instead
of a regular phone line is called Voice
over Internet (VoIP). VoIP converts
the voice signals into a digital signal
that travels over the Internet. VoiP can
allow the users to make a call directly
from a computer, a special VoIP
phone, or a traditional phone using an
adapter.
• Voice mail is a communication
services that function much like as
answering machine allowing the
caller to leave a message for the
called person or party. The only
difference is that the computer in the
Voice Mail System converts the
analog voice message into digital
form and stored it in s voice mail
box, which is a storage location on a
computer in the Voice Mail System.
• Voice Mail Box provides
individual voice mail box for many
users. By accessing the caller’s
voice mail box, the called party
can listen to the message, add a
comment and reply or forward the
message to another voice mail
box in the voice mail system.
• Web Log is a chronologically
arrange web pages that short,
frequently updated post with the
latest entry appearing at the top of
the page. Web log is usually
called Blog. “To blog” means to
write on one’s weblog and as a
noun, blog is an online journal or
web diary, or an online publishing
platform.
Category of Bloggers
• Personal bloggers create blogs that
contain diary or journal-type entries
• Business bloggers create blogs to
promote their products and/or services
• Organizational bloggers found in
corporations, educational institutions,
non-profit organizations, and in some
other community clubs.
• Professional bloggers are persons
who are actually hired to blog