Introduction to information and
communication system
Information:
The processed data or some data
which is useful, conveying some message and sense that is called information.
Types of information:
- Constructional/creative information
- Operational information
- Communication information
Constructional/creative information
This includes all information that
is used for the purpose of producing something. Before anything can be made,
the originator mobilizes his intelligence, his supply of ideas, his know-how,
and his inventiveness to encode his concept in a suitable way.
There are many types e.g. technical
drawings for the construction of a machine, a cake recipe, details of the
chemical processes, an electrical circuit diagram, or the genetic information
required for the construction of a living cell.
Operational information
All concepts having the purpose of
maintaining some “industry” in the widest sense of the word are included under
this kind of information. Many systems require operational information in the
form of programs for proper functioning.
E.g. the operating system of a
computer (e.g., DOS programs), the program controlling a robot or a process
computer, warning systems for airplanes and ships.
Operational information in the
animal kingdom, which we call “instincts” because of our lack of knowledge
about their codes and methods of transfer.
Communication information
This is composed of all other kinds
of information, e.g., letters, books, phone calls, radio transmissions, bird
songs, and the message of the Holy Scriptural book.
These information does not include
the construction of a product, neither is it involved in maintaining some
process
The goals are transmission of a
message, spreading joy, amusement, instruction, and personal confidences
Analog and Digital Information
The term analog is used to refer to
the natural world, where time is continuous and most parameters(like light,
sound Intensity, position etc.) can vary smoothly and continuously over some
range, taking on an infinite number of possible values. The term digital is
used to refer to information representations for which both time and the value
being measured move in discrete steps i.e. when there are a finite number of
possible values.
The Natural World is Analog
Human speech is an example of analog communication.
Speech causes to vibrate with varying amplitude (volume) and frequency (pitch).
The computer World is Digital
·
Digital
computers communicate using 2 discrete values. In other words, they speak in
binary (0 and 1).
·
Of
course, 0s and 1s are not literally transmitted
·
In
an electrical network, variations in voltage represent one of the two values.
·
In
an optical network, pulses of light provide the discrete values.
·
The
pulses of light or voltage variations are the “signal”.
·
Two
values in different combinations sufficiently encode text, number, image and
sound.
·
Recall
that the telegraph was an early example of communications using discrete,
electrical pulse transmission.
Information system:
A combination of hardware, software,
infrastructure and trained personnel organized to facilitate planning, control,
coordinate and decision making in an organization.
Communication Modes:-
It refers to the direction of flow of signals among linked devices.
There are three ways for transmitting data from one point to another
1. Simplex Mode
2. Half-Duplex Mode
3. Full-Duplex Mode
1. Simplex Mode:
•
Features:
a)
Unidirectional
b)
Send-only
or Receive-only devices
c)
Sender
is unaware about the status of transmission.
d)
Rarely
used for data communication.
Example: Radio and T.V transmissions
2. Half-Duplex Mode
•
Features:
a)
Two-way
communication but not simultaneously.
b)
At a
moment it is unidirectional only.
c)
Can
alternately send and receive data.
d)
Transmission
direction can be changed whenever
required.
e)
Delay
factor (Line Tumaround Time) is associated.\
Example:
1) Wireless handsets used by
military personnel.
2) Internet browsing
3. Full-Duplex Mode:
•
Features:
a)
Also
known as Duplex Mode
b)
Communication
in both directions simultaneously.
c)
Line
Tumaround time is eliminated.
d)
Much
efficient mode
Example: Telephone communication system
