Data communication refers to the transfer of data from one location to another, involving elements such as a transmitter, receiver, medium, and message. There are two main types of media for communication: guided (physical links like cables) and unguided (natural environmental links like atmospheric transmission). Additionally, data transmission can occur in three modes: simplex (one-way), half-duplex (two-way, but one direction at a time), and full-duplex (simultaneous two-way communication).

1. DATA
COMMUNICATION

2. Data Communication
The transfer of data or information from one
location to another is called data
communication or data transmission.
ELEMENTS OF DATA COMMUNICATION SYSTEM
Transmitter or sender or source
Receiver or sink or destination
Medium
Message

3. Transmitter
The computer or device that is used for
sending the data from one location to other is
called transmitter.
In electronic data communication, computer
is usually used as transmitter.
Receiver
The computer or device that receives the
data is called receiver.
It is also known as ‘sink’. The receiver can be
a computer, printer or a fax machine.
Elements of Data Communication

4. Elements of Data Communication
Medium
The path or link through which data is
transferred from sender to receiver is called
medium.
Message
The data or information which is sent from
sender to receiver is called message”. It is
the main element of data communication
system, due to which data communication
occur.

5. The path or link through which data is
transferred from sender to receiver is called
medium”.
There are two main categories of data
communication media.
Guided Media
Unguided Media
Communication Media

6. GUIDED MEDIA
Guided media are the physical links through
which signals are transferred. These are also
called bounded media. These include various
types of cables. The type of cable chosen for a
network depends upon the network’s topology,
size and speed.
Commonly used guided media include
coaxial cables, wire pairs and fiber-optic
cables.
Communication Media

7. UNGUIDED MEDIA
Unguided media are the logical links through
which signals are transferred. These are the
natural parts of environment that can be used
to transfer signals in the form of waves. The
atmosphere and space are examples of
unguided media.
Commonly used methods of transmission
through unguided media are microwave and
satellite transmission.
Communication Media

8. The manner in which data is transmitted from
one location to another is called data
transmission mode.
There are three different modes for
transmitting data from one location to another.
Simplex Mode
Half Duplex Mode
Full Duplex Mode
DATA COMMUNICATION MODES

9. SIMPLEX MODE
In simplex mode, data is transmitted in only on
direction. A terminal can only send data and
cannot receive data or it can only receive data but
cannot send it. In this mode, the flow of
information is
uni-directional. It is not possible to confirm
successful transmission of data. So it is rarely
used for data communication.
Data Communication Modes
Sender Receiver

10. Use:
This mode is normally used for Remote control
devices in which one device can only send data
and other can only receive data. TV remote control
is an example of Simplex mode.
Data Communication Modes

11. HALF-DUPLEX MODE
In half-duplex mode, data can be transmitted in
both directions, but only in one direction at a time.
Therefore data can be sent and received
alternatively. Its disadvantage is that a lot of time is
wasted in changing direction of flow of data. So,
the transmission rate for this mode is slow.
Data Communication Modes
Sender/Receiver Receiver/Sende
r

12. Use:
It is possible to confirm the transmission of
data in this mode. So this is normally used in
wireless communication system.
Data Communication Modes

13. FULL-DUPLEX MODE
In full-duplex mode, data can be transmitted in
both directions at the same time. In this mode, no
time is wasted in changing direction of flow of data
like Half-duplex mode. Therefore it is the fastest
and most efficient mode.
Data Communication Modes
Sender/Receiver Receiver/Sende
r

14. Use:
Telephone communication is an example of
full-duplex mode.
Mobile phone communication is an example
of full duplex mode.
Data Communication Modes