Intro to Data Communication

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FUNDAMENTAL OF

NETWORKING

TOPIC 1

Introduction to DataCommunication


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1-1 DATA COMMUNICATIONS

The term telecommunication means communication at a

distance. The word datarefers to information presented inwhatever form is agreed upon by the parties creating and

using the data. Data communicationsare the exchange of

data between two devices via some form of transmission

medium such as a wire cable or radio links (wireless).

Components of a data communications system

Data Flow

Topics discussed in this section:


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1.

Figure 1.1 Components of a data communication system

1 2

!


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1-1 DATA COMMUNICATION SYSTEM

There are FOURbasic elements involved in Communication

ystem.

Sender : ender is the party which initiates the

communication.

Medium : !edium is the mechanism by which the

communication is conveyed to the receiver.

Receiver: "eceiver is the one who receives the signal sent

by the sender.Message : !essage is the information content that is

between the sender and receiver via the medium.


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1-3 TRANSMISSION MODE

There are TWO types of transmission mode.

1. Synchronous # The transmission of data in which the

transmitter and receiver are synchronized is called

synchronous Transmission. Code are sent from the

transmitting station to the receiving station to establishthe synchroni$ation and data is then transmitted in

continuous streams.

2. Asynchronous # The asynchronous transmission is a

techni%ue widely used in personal computers to provide

connectivity to printers& modem& fax machines& etc. The

most significant aspect of asynchronous transmission is

that codes are sent in an untimely manner& with uneven

intervals between characters.


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Figure 1.2 Data flow (simplex& half'duplex& and full'duplex)


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1-3 TRANSMISSION MODE


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1-4 COMMUNICATION MODE

There are TR!! types of communication mode.

. implex ' n simplex mode& the communication can take

place in one direction. !.g radio and tv.

*. +alf'duplex # n half'duplex mode communication

channel is used in both directions& but only one directionat a time. ,.g walkie'talkie& !orse code

-. ull'duplex # The communication channel is use in both

direction at the same time. ,.g telephone line


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Figure 1.2 Data flow (simplex& half'duplex& and full'duplex)


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1-5 NETWORKS

/ network is a set of devices (often referred to as nodes)connected by communication links. / node can be a

computer& printer& or any other device capable of sending

and0or receiving data generated by other nodes on the

network. / link can be a cable& air& optical fiber& or anymedium which can transport a signal carrying

information.

Network Criteria

Links

Topics discussed in this section:


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Network Criteria

Performance

Depends on Network Elements

Measured in terms of Delay and Trougput

Reliability

Failure rate of network components Measured in terms of a!aila"ility#ro"ustness

Security

Data protection against corruption#loss of data due

to$

Errors

Malicious users

1-6 Network Criteria


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Te throughputor bandwidthof a cannel is te

num"er of "its it can transfer per second

Te latencyordelayof a cannel is te time tatelapses "etween sending information and te earliest

possi"le reception of it

Terminology


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E%ercise

a. W$at i% t&'&communication(). Di%cu%% *$at i% n&t*or+ crit&ria.

c. T$&r& ar& t,-&% o communication mod&. Dra*and )ri&/, &0-'ain &ac$.

Intro to Data Communication

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