UNIT2
COMMUNICATION AND
NETWORK CONCEPTS
PART 3
NETWORK DEVICES
Computer hardware devices which are used to
connect computers, printers, or any other
electronic device to a computer network are
called network devices.
These devices transfer data in a fast, secure
and correct way with some specific
functionality over same or different networks.
Some devices are installed on the device, like
internal modem, NIC card or RJ45 connector,
whereas some part of the network, like router,
switch, etc.
NIC(NETWORK INTERFACE
CARD)
Mostly used networking
device is also known as
Network Adapter Card,
Ethernet Card and LAN card.
It allows our PC to
communicate with other PCs.
A PC uses parallel data
transmission to transmit data
between its internal parts
whereas the media that
connects this PC with other
device/PCs uses serial data
transmission.
A NIC converts parallel data
stream into serial data stream
and vice versa.
RJ-45(Registered Jack- 45)
RJ-45 is an eight
wired connector
that is used to
connect computers
on a local area
network (LAN)
especially Ethernet.
HUB
HUB is used to connect multiple
computers in a single LAN network of one
workgroup.
Generally HUB are available with 4, 8, 12,
24, 48 ports.
When a hub receives signal on its port, it
repeats the signal and forwards that
signal from all ports except the port on
which the signal arrived.
There are two types of HUB.
Passive HUB - It only forwards the signal
on all ports without amplifying the signal.
Active HUB - It forwards the signal with
improvement in the quality of data signal
by amplifying it. That why such hubs need
additional power supply.
Based on port type: There are two
types HUB.
Ethernet HUB: All ports have RJ-45
connectors.
Combo HUB: Several different types of
connectors such as RJ-45, BNC and AUI
available as ports in such HUB.
SWITCH
Switch is also used to connect
multiple computers together in
a LAN workgroup, just like hub.
Switches are available with 4,
8, 12, 24, 48, 64 ports.
Switch makes their switching
decisions by using application
specific integrated circuits.
Due to switching decision
capability, switch sends signal
to recipient only and that’s
why switches are called as
intelligent hub.
Repeater
In a network signal travels
a long distance in
transmission media.
Due to resistance of media
signal becomes weak.
Repeater is a networking
device which regenerates
the signal and forwards
these signal with more
power.
MODEM
MODEM is short for Modulator
Demodulator.
It’s an electronic device used to
access the Internet that
modulates carrier waves to
encode information to be
transmitted and also demodulates
incoming carrier waves to decode
the information they carry.
Modulation means digital to
analog signal conversion and its
vice versa is known as
demodulation.
Router
Router is a networking device
which chooses the best optimal
path from available paths to
send the signals.
It interconnects different
networks.
The simplest function of a router
is to received packets from one
connected network and pass
them to second connected
network.
Wi-Fi cards (Wireless Fidelity
Cards)
Wi-Fi cards are small and portable cards that
allow our computer to connect to the Internet
through a wireless network.
Wi-Fi transmission is through radio waves,
these signals are picked up by Wi-Fi receivers
such as computers and cell phones equipped
with Wi-Fi cards.
The devices need to be within the range of a
Wi-Fi network to receive the signals and
produces a wireless Internet connection.
Once a connection is established between
user and the network, the user is prompted
with a login screen and password for
establishing a secure connection.
Wi-Fi cards can be external or internal. If a
Wi-Fi card is not installed inside our computer,
we may purchase an external USB antenna
attachment and connect it to our device.
Many computers and mobile devices are
nowadays equipped with wireless networking
capability and do not require a Wi-Fi card.
