This document provides an overview of data communication concepts presented by lecturer Muhammad Shoaib. It defines data communication as the exchange of data between two devices via transmission. The key components of data communication are identified as the message, sender, receiver, transmission medium, and protocol. Different data types, communication modes (simplex, half-duplex, duplex), network classifications (point-to-point, multipoint), communication channels (guided media like twisted pair, coaxial cable, optical fiber and unguided media like terrestrial microwave, satellite, broadcast radio, infrared), and the role of communication protocols are described.

1. Lecturer: Muhammad Shoaib
Office R-03, Amin Campus
faraz.khan@tuf.edu.pk
041 8750971 ext 339
Data
Communication

2. Data Communication
Data Communications are the exchange of data
between two devices via some form of
transmission.
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3. 1. Message: data.
2. Sender: The device that send the message.
3. Receiver: The device that receive the message.
4. Transmission Medium: The physical path between sender and receiver, the
message travel.
5. Protocol: Is a set of rules that governs data communication. It represents an
agreement between the communicating devices. Without a protocol, two devices
may be connected but not communicating.
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Receiver
Sender
Message
Rules…
Protocol
Transmission Medium Rules…
Protocol

4. Data Representation
Text
Numbers
Images
Audio
Video
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5. Data Communication Modes
Simplex: In simplex mode, data can flow in
only one direction.
Always one side sender and another side
receiver.
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Remote Control
TV

6. Data Communication Modes cont.
Half-Duplex: In half-duplex mode, data can
flow in both directions but only in one
direction at a time.
Walki-Talki
Each side maybe sender or receiver but not a
same time.
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In different time
© Engr Faraz Khan www.tuf.edu.pk

7. Data Flow in Communication cont.
Duplex: two-way concurrent.
Computer network
Mobile Network
Each side sender and receiver at same time.
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At same time
© Engr Faraz Khan www.tuf.edu.pk

8. Network Classification
Upon the transmission medium (type of connection):-
1. Point-to-point: A pair of nodes connected together via
dedicated link.
2. Multipoint: Number of node connected and share a single
link.
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PC PCLink
PCPCPC
Link
© Engr Faraz Khan www.tuf.edu.pk

9. Communication Channels
Communication channel is a connection between transmitter
and receiver through which Data can be transmitted.
Communication channel also called as communication media
or transmission media
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10. Types of Communication channel
Twisted
pair
Coaxial
cable
Optical
fiber
Satellite
microwave
Terrestrial
microwave
Broadcast
radio
• Other types are Under Water Acoustic Channels, Storage Channels like
magnetic tapes, magnetic disks etc.

11. Guided Media
Twisted Pair
Coaxial Cable
Fiber Optic
© Engr Faraz Khan www.tuf.edu.pk 11

12. Twisted-pair
cable
One of the wires carries signal,
the other is used only as a ground
reference.
Number of twists per unit length
determines the quality of the
cable.

13. Coaxial cable
• Used for both analog and digital
signals
• Effectively used at higher data
rate and higher bandwidth
• For analog signals need
amplifiers every few km
• For digital signals requires
repeater every 1km

14. Optical fiber
Its a flexible, transparent fiber made of high
quality glass (silica) or plastic, slightly thicker
than a human hair. It can function as
a waveguide, or “light pipe”, to transmit light
between the two ends of the fiber
Optical fibers are widely used in fiber-optic
communications, which permits transmission
over longer distances and at
higher bandwidths (data rates) than other forms
of communication.
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15. Unguided Media (wireless communication medium)
Terrestial Microwave
Satellite Communication
Broadcast Radio
Infrared
© Engr Faraz Khan www.tuf.edu.pk 15

16. Terrestrial microwave
Requires fewer repeaters
Use a parabolic dish to focus a
narrow beam.
1-40GHz frequencies
Used in Mobile communication

17. Satellite communication
Receive on one frequency, and
transmits on another frequency
eg. uplink 5.925-6.425 GHz &
downlink 3.7-4.2 GHz
• Height 35,784km
• Spaced at least 3-4° apart

18. Broadcast Radio
Radio frequency range is 3kHz to 300GHz
Use broadcast radio of 30MHz - 1GHz, for:
FM radio
UHF and VHF television
Is a unidirectional
Suffers from multipath interference
 Reflections from land, water, other objects
Are used for multicasts communications, such as radio and
television, and paging system.

19. Infrared Communication
This is one of the earliest types of optical
communication and is still very much in use today.
It is found in remote controls for televisions, DVD
players and most entertainment devices.
Infrared uses light that is invisible to us and is just
above the red end of the color spectrum.
The key component of an infrared system is an
infrared LED to emit light and a photodiode in the
television or equipment to receive the light.
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20. What is a Communication Protocol?
A Protocol is a set of rule that governs data communication.
For two entities to communicate successfully, they must “speak
the same language”.
What is communicated, how it is communicated, and when it is
communicated must conform.
These conventions are referred to as a protocol.
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21. Thank You !
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