Very Easy and Accurate material for learning.

1. Project Name:
“Data Communication”
Group:
Sundas :62
Awais ch :67
Saddique: 81
Hussnain :74
Meesha :57
Subject:
“Business It”

2. Beginning……
Data communication :

3. Data communication :
It is refers to the exchange of data between a source and a receiver. Data communication
is said to be local if communicating devices are in the same building or a similarly
restricted geographical area.
Datum:
It means the facts information statistics or the like derived by calculation or
experimentation. The facts and information so gathered are processed in accordance
with defined systems of procedure. Data can exist in a variety of forms such as numbers,
text, bits and bytes. The Figure is an illustration of a simple data communication system.
Components of data communication system:
1. Message:

4. It is the information or data to be communicated. It can consist of text, numbers,
pictures, sound or video or any combination of these.
2. Sender:
It is the device/computer that generates and sends that message.
3. Receiver:
It is the device or computer that receives the message. The location of receiver
computer is generally different from the sender computer.
Medium:
It is the channel or physical path through which the message is carried from
sender to the receiver
Protocol:
It is a set of rules that govern the communication between the devices. Both
sender and receiver follow same protocols to communicate with each other.
Protocol

5. It performs the following functions:
 Data sequencing.
 Data routing.
 Data formatting.
 Flow control.
 Error control.
 Precedence and order of transmission.
 Connection establishment and termination.
 Data security
 Log information

6. Network Modes:
The way in which data is transmitted from one place to another is called data transmission mode.
It is also called the data communication mode. It is indicates the direction of flow of information.
Sometimes, data transmission modes are also called directional modes.
Types of Data Transmission Modes:
1. Simplex mode
2. Half-duplex mode
3. Full-duplex mode
Simplex Mode:
In simplex mode, data can flow in only one direction. In this mode, a sender can only send
data and cannot receive it. Similarly, a receiver can only receive data but cannot send it. Data
sent from computer to printer is an example of simplex mode.
In simplex mode, it is not possible to confirm successful transmission of data. It is also not
possible to request the sender to re-transmit information. This mode is not widely used.
However, this mode is used in business field at certain point-of-sale terminals. The other
Examples:
 Radio
 T.V transmissions.

7. Half-Duplex Mode:
In half-duplex mode, data can flow in both directions but only in one direction at a time. In
this mode, data is sent and received alternatively. It is like a one-lane bridge where two-way
traffic must give way in order to cross the other.
Example:
The Internet browsing is an example of half duplex mode. The user sends a request to a Web
server for a web page. It means that information flows from user's computer to the web server.
Web server receives the request and sends data of the requested page. The data flows the Web
server to the user's computer. At a time a user can a request or receive the data of web page.
Full-Duplex Mode:
In full duplex-mode, data can flow in both directions at the same time. It is the fastest
directional mode of data communication.
Example:
The telephone communication system is an example of full-duplex communication mode. Two
persons can talk at the same time. Another example of fully-duplex mode in daily life is
automobile traffic on a two-lane road. The traffic can move in both directions at the same time.
Data Transmission Network:
 LAN
 WAN
 MAN
 PAN
 VPN

8. Types of Data Transmission
Network:
Local Area Network (LAN)
LAN stands for Local Area Network. It covers, as the name suggests, a local area. This usually
includes a local office and they're also pretty common in homes now, thanks to the spread of Wi-Fi.
LAN is based on Ethernet.There are two ways to implement Ethernet.
Wide Area Network (WAN)
It refers to a wide area network. The name is exactly what it sounds like: a network that covers an
area wider than a LAN. Beyond that, the definition is less clear. Distances can range from a network
connecting multiple buildings on a corporate or college campus to satellite links connecting offices in
different countries. The most popular WAN is the one you're using to read this article: the Internet.
It's actually a collection of other networks, including other LANs and WANs.
Example:
WANs can be wired, using fiber-optic cable, for example, or wireless. A wireless WAN might use
microwave or infrared (IR) transmission technology, or even satellite.

9. Virtual Private Network (VPN)
Another method that has become popular in recent years is the use of a virtual private network, or
VPN. It uses the Internet to allow people to log into a network remotely and access its resources, but
encrypts the connection to thwart eavesdroppers. If your company sets you up with a VPN, you can
access your corporate intranet, file servers or email from home or a coffee shop - just as if you were
using it in your office. This makes VPN a popular way to support remote workers, especially in fields
where privacy is paramount, such as healthcare. Windows, Mac OS X and many Linux distributions
can act as VPN clients right out of the box.
Personal Area Network (PAN)
PAN stands for personal area network, and again, it's exactly what it sounds like: a network covering
a very small area, usually a small room. The best known wireless PAN network technology
is Bluetooth, and the most popular wired PAN is USB. You might not think of your wireless headset,
your printer or your smartphones as components in a network, but they are definitely talking with
each other. Many peripheral devices are actually computers in their own right. Wi-Fi also serves as a
PAN technology, since Wi-Fi is also used over a small area.
Metropolitan Area Network (MAN)
A metropolitan area network (MAN) connects nodes located in the same metro area. For example, a
company located in the San Francisco Bay Area might have its buildings in San Francisco, Oakland
and San Jose linked together via a network.
One of the most common ways for organizations to build this kind of network is to use microwave
transmission technology. You might have seen a microwave antenna on a TV news van, extended
high in the air, beaming video and sound back to the main TV studio.

10. Network Topologies:
Think of a topology as a network's virtual shape or structure. This shape does not
necessarily correspond to the actual physical layout of the devices on the
network.
Example:
The computers on a home LAN may be arranged in a circle in a family room, but
it would be highly unlikely to find a ring topology there.
Network topologies are categorized into the following basic types:
 Bus
 Ring
 Star
 Tree
 Mesh

11. More complex networks can be built as hybrids of two or more of the above basic
topologies.
 Bus Topology
Bus networks (not to be confused with the system bus of a computer) use a
commonbackbone to connect all devices. A single cable, the backbone functions
as a shared communication medium that devices attach or tap into with an
interface connector. A device wanting to communicate with another device on the
network sends a broadcast message onto the wire that all other devices see, but
only the intended recipient actually accepts and processes the message.
Bus Topology Diagram
Ring Topology
In a ring network, every device has exactly two neighbors for communication
purposes. All messages travel through a ring in the same direction (either
"clockwise" or "counterclockwise"). A failure in any cable or device breaks the
loop and can take down the entire network.

12. Ring Topology Diagram
Star Topology:
Many home networks use the star topology. A star network features a central
connection point called a "hub node" that may be a network
hub , switch or router . Devices typically connect to the hub with Unshielded
Twisted Pair (UTP) Ethernet.
Compared to the bus topology, a star network generally requires more cable.
Star Topology Diagram

13. Tree Topology:
Tree topologies integrate multiple star topologies together onto a bus. In its
simplest form, only hub devices connect directly to the tree bus, and each hub
functions as the root of a tree of devices. This bus/star hybrid approach supports
future expandability of the network much better than a bus (limited in the number
of devices due to the broadcast traffic it generates) or a star (limited by the
number of hub connection points) alone.
Tree Topology Diagram

14. Mesh Topology:
Mesh topologies involve the concept of routes. Unlike each of the previous
topologies, messages sent on a mesh network can take any of several possible
paths from source to destination. (Recall that even in a ring, although two cable
paths exist, messages can only travel in one direction.) Some WANs , most
notably the Internet, employ mesh routing.
A mesh network in which every device connects to every other is called a full mesh. As
shown in the illustration below, partial mesh networks also exist in which some devices
connect only indirectly to others.

15. ADVANTAGES OF COMMUNICATION:
 Speeds the sending of information:
Communication technology tools like electronic mail and text messaging systems speed up
the sending of information within and outside of the organization.
 Improves organizational communication:
Communicationtechnologyhelpsinthe creationof ashared informationenvironmentinan
organization. Organizationinformationisorganizedinone central location,allowinganyone access
that informationastheyneed.
 Speeds decision making in an organization:
Since communicationtechnologyspeedsthe transferof information,employeesinanorganization
can easilyconsulteachotherandanalyze informationinashortestperiodandmake adecision.
 Increases participation in organizational processes:

16. Everyemployee will have aspecifictasktocomplete andall thiscan be monitoredremotelybythe
manager.So all partieswill be active since theirworkisbeingmade simplebyeasycommunication.
 Influences the way people interact in organizations:
An organizationwere youonlysee the operationsmanagertwice aweek,bythe time he comes,
everyone will needtospeaktothemand theywill have lesstime foreachof you.Butwithelectronic
mail,youcan simplydraftan email andsenditto yoursuperioror workmate.
 Structures organizational life:
Communicationtechnologyputs everythingwhere itissupposedtobe.Noneedtosee papersand
fileseverywhere inthe office.All dataisstoredonthe database,andyou will have lesspaperwork
inthe organizationwhichmakeslife easieratwork.
 Supports open discussions:
Most organizationhave usedthe internettocreate organizational forumswhere membersof the
organizationcandiscussaboutvariousissuesandgeta solution.Inthiscase memberscansuggeston
areas of improvementwithinthe organization.
 Eliminates stereotypical classifications:
It reflectsaselectedfew of the racial demographics.Withcommunicationtechnology,all thiswillbe
eliminatedbecausethere isnoface-to-face communication.Stereotypingof employeescanresult
intopoor performance andlackof self-esteemamongstemployees,so itisa wrong character.
 Provides a voice to those who normally would not speak up in
groups:
Face-to-face communications tends to be difficult to some people, so the use of
communication technology will help them communicate effectively at work.
DISADVANTAGES OF COMMUNICATION TECHNOLOGY IN
AN ORGANIZATION:
 Poor substitute for face-to-face communication:
Since employees are using machines to communicate, they get less time to talk to each
other and know each other better. This has resulted into increased bad relationships at
work.
 Difficulty Training Employees:
If an organization deploys a new communication technology system, they will have to pay
an extra fee to train employees in the organization to use that technology effectively.

17.  Expensive:
It can be very expensive to install a new communication technology system in a very big
organization.
 Not Safe:
Information has been centralized less than one database; it is exposed to people with wrong
intention within the organization.
Communication Devices:
Communication device is a hardware device capable of transmitting
an analog or digital signal over the telephone, other communication
wire, or wirelessly. The best example of a communication device is a
computer Modem, which is capable of sending and receiving a signal to
allow computers to talk to other computers over the telephone. Other
examples of communication devices include a network interface
card(NIC), Wi-Fi devices, and an access point. Below is a picture of
some of the different types of Wi-Fi devices that are all examples of a
communication device.

18. Communication device examples
Below is a full listing of all the different types of communications devices you
may encounter when dealing with a computer.
 Bluetooth devices
 Infrared devices
 Modem (over phone line)
 Network card (using Ethernet)
 Smartphone
 Wi-Fi devices (using a router)
Physical Transmission:
It uses wire, cable, and other physical materials to send communications
signals.
Examples of physical transmission media are
Twisted-pair cable
Coaxial cable
Fiber-optic cable

19. Fiber optic:
Fiber optic cabling consists of a center glass core surrounded by several layers of
protective materials. It transmits lights rather than electronic signals thus eliminating
electrical interference, this makes it suitable for areas that contain large amount of
electrical interferences. In addition it has the ability to transmit signals over much
longer distance, carry more information at a faster speed than coaxial and twisted
pair. More over cables are much thinner and light weighted.
Coaxial cable:
Coaxial cabling has a single conductor as it center. A plastic layer provides insulation
between the center conductor ad the braided mental shield. The metal shield help to
block any outside interference from fluorescent lights, motors, and other computers .
Its difficult to install, but its highly resistant to signal interference, it supports greater
cable length between network devices than twisted pair. Two type of coaxial cable
are: thick coaxial and thin coaxial.
Twisted-pair cable:
The cable has four pairs of wires inside the jacket. Each pair is twisted with a
different number of twists per inch to help eliminate interference from adjacent pairs
and other electrical devices. The tighter the twisting, the higher the supported
transmission rate and the greater the cost per foot.

20. Wireless Transmission Media –
Send communications signals through air or space. Used when inconvenient,
impractical, or impossible to install cables.
Types Wireless Transmission Media

21.  Broadcast Radio
 Bluetooth:
 Cellular Radio
 Personal Communication Services (PCS)
 Microwaves
 Uses line-of-sight transmission
 Communications
 Infrared

22. Thank You