Course code : CSE-313
Course title : Data communication
Pranab Bandhu Nath
Dept. of CSE
ID : 1834902165
Batch : 49th
Dept. of CSE
Submission date: 06/09/2021
Data transmission mode : Data Transmission mode defines the
direction of the flow of information between two communication devices. It is also
called Data Communication or Directional Mode. It specifies the direction of the
flow of information from one place to another in a computer network.
Figure : Types of transmission mode Simplex
mode: Simplex is the data transmission mode in which the data can
flow only in one direction, i.e., the communication is unidirectional. In
this mode, a sender can only send data but can not receive it. Similarly, a
receiver can only receive data but can not send it.
Half-duplex mode: Half-duplex devices can only transmit in one
direction at one time. With half-duplex mode, data can move in two
directions, but not at the same time. The term duplex, on its own,
refers to the capability to send and receive data. Duplex is often used
when talking about conversations over a telephone or computer.
Full-duplex : Full-Duplex is the data transmission mode in which
the data can flow in both directions at the same time.It is two-way
communication in which both the stations can transmit and receive the
data simultaneously. Full-Duplex mode has double bandwidth as
compared to the half-duplex.
Data signal : Data signal is a method of how information is
transferred; usually it's transferred in binary code in signals or pulses
and may be contained in a packet.
There are four possible combinations of data and signal types:
• Analog data, analog signal;
• Digital data, analog signal;
• Analog data, digital signal;
• Digital data, digital signal.
Aanalog signal : An analog signal signifies a continuous signal
that keeps changes with a time period. A digital signal signifies a
discrete signal that carries binary data and has discrete values. Digital
signal is square waves.
Digital signal : A digital signal is a signal that is being used to
represent data as a sequence of discrete values; at any given time it
can only take on, at most, one of a finite number of values.
Internet : The Internet is a vast network that connects
computers all over the world. Through the Internet, people can
share information and communicate from anywhere with an
Intranet : An intranet is a computer network for sharing
information, collaboration tools, operational systems, and
other computing services within an organization, usually to the
exclusion of access by outsiders.
Computer network : computer network is a set of computers
sharing resources located on or provided by network nodes. The
computers use common communication protocols over digital
interconnections to communicate with each other.
LAN : A local area network is a computer network that
interconnects computers within a limited area such as a
residence, school, laboratory, university campus or office
building. By contrast, a wide area network not only covers a
larger geographic distance, but also generally involves leased
MAN : A metropolitan area network is a computer network that
interconnects users with computer resources in a geographic
region of the size of a metropolitan area.
WAN : A wide area network is a telecommunications network
that extends over a large geographic area for the primary
purpose of computer networking. Wide area networks are often
established with leased telecommunication circuits.
PAN : A personal area network is a computer network for
interconnecting electronic devices within an individual
person's workspace. A PAN provides data transmission among
devices such as computers, smartphones, tablets and personal
Hub : An Ethernet hub, active hub, network hub, repeater hub,
multiport repeater, or simply hub is a network hardware device
for connecting multiple Ethernet devices together and making
them act as a single network segment
Swicth : A network switch is networking hardware that
connects devices on a computer network by using packet
switching to receive and forward data to the destination device.
A network switch is a multiport network bridge that uses MAC
addresses to forward data at the data link layer of the OSI
Router : A router is a networking device that forwards data
packets between computer networks. Routers perform the traffic
directing functions on the Internet. Data sent through the
internet, such as a web page or email, is in the form of data
Network or data communication addressing :
1. Physical addressing : MAC
2. Logical addressing : IP address
OSI model : OSI stands for Open System
Interconnection. There are 7 layers in the OSI model and
each layer has a different capability.
Work of OSI model : The OSI reference model
describes how data is sent and received over a network. This
model breaks down data transmission over a series of seven
layers. Each layer has a responsibility to perform specific
tasks concerning sending and receiving data. All of the layers
are needed for a message to reach its destination. iThe 7
layer’s of the OSI model :
2.Data link layer.
Physical layer : In this layer transmit bit's over a medium
and identify NIC.
Data link : In this layer organized bits into frame to provide
hop- to – hop delivery and identify the MAC address.
Network layer : In this layer the packets moves form
source to destination to provide internetworking.Transport
layer : This layer provide reliable process to process message
delivery and error delivery.
Session layer : The session layer controls the
conversations between different computers. Session layer
services also include authentication and reconnections.
Presentation layer : This layer translate, encrypt and
Application layer : This layer provide allow access to
TCP /IP model : It stands for Transmission Control
Protocol/Internet Protocol. The TCP/IP model is a concise
version of the OSI model. It contains four layers, unlike seven
layers in the OSI model.
The 4 layer of TCP/IP model:
3. Internet layer.
4.Network interface layer.
OSI Model vs TCP/IP Model
Difference between Broad band and
Broad band :
• Used for Analog signal.
• Transmission is unidirectional in nature.
• Signals can be travelled over long distances
without being attenuated.
• It is used with a bus as well as tree topology.
• Only PSK encoding is used.
• Depends on ASK,FSK,PSK speed.
• Used for Digital signal.
• Transmission is bidirectional in nature and it
provide binary value directly through Voltage.
• Signals can only travel over short distances.
• It works well with bus topology.
• In baseband transmission, Manchester and
Differential Manchester encoding are used.
Transmission impairment : Signals
travel throughtransmission media, which are not
perfect. The imperfection causes signal
impairment. This means that the signal at
thebeginning of the medium is not the same as
the signal at the end of the medium.
Types of Transmission impairment :
Attenuation : Attenuation is the loss of signal strength in
networking cables or connections.
Noise : Noise Impairment occurs when an unwanted signal is
inserted between transmission and reception.
Data modulation : Data modulation is a process
converts analog signals into digital signals and digital
signals into analog signals. Computers store and process
data in digital format. Data modulation allows computers to
store and process analog signals.
• When data is sent over physical medium.it means to
first convert into electromagnetic signal.Data itself
can be converted into signal.
• Signal : 1.Analog signal :- Human voice.
2.Digital signal :- Document on a Disk.
Data signal : A pulse or frequency of electricity or
light that represents data as it travels over a network, a
computer channel or wireless. Contrast with control signal.
Digital modulation : Digital modulation is the
process of encoding a digital information signal into the
amplitude, phase, or frequency of the transmitted signal.
Types of Digital modulation :
1. ASK ( Aplititude shift keying).
2. FSK (Frequency shift keying).
3. PSK (Phase shift keying).
• Use optical fiber.
• If signal on it’s provide 1
• If signal off ityprovide 0
• Use Coaxial cable.
• In High frequency it’s provide 1
• In low frequency it’s provide 0.
• Use Router or Brouter.
• BPSK :- Two phase binary shift keying.
• QPSK :- Four phase Quadrature shift keying.
➢ All contents are from Pranab Bondhu Nath sir’s class
lectures and Picture’s from: