Transmission media enables computers to communicate by sending and receiving messages through various means. There are two types of transmission media: guided and unguided. Guided media uses cabling to bind data signals to a specific transmission path, including twisted pair, coaxial cable, optical fiber, and open wire. Unguided media transmits data signals through the air without a transmission path, including radio frequencies, microwave, and satellite transmission. The appropriate transmission medium depends on the network and distance between communicating devices.

1. Case study
Transmission Media
1). Introduction:-
 On any network, the various entities must communicate
through some form of media.
 Just as humans can communicate through telephone wires or
sound waves in the air, computers can communicate through
cables, light, and radio waves.
 Transmission media enables computers to send and receive
messages but do not guarantee that the messages will be
understood.
 Therefore transmission media is compulsory for
communication.
2).Defination and Example:-
Defn
:-
Example:-
3). Classification:-
There are two types of transmission media:
A). Guided media.
There are four types are as follows:
i). Open wire.
ii). Twisted pair.
iii). Coaxial cable.
iv). Optical fibre.
B). Unguided media.

2. They are classified by the type of wave propogation:
i). Radio frequencies.
ii). Microwave.
iii). Satellite.
4). Description & Application:-
A). Guided Media:
 Uses a “Cabling” system that gudes or bounds the data signals
along a specific path.
 The data signals are bound by the “Cabling” system.
 Guided media is also known as bound media.
 Cabling is meant in a generic sense in the previous sentences
and is not meant to be interpreted as copper wire cabling only.
There are four basic types of guided media:
i). Open wire:
 Open wire is traditionally used to describe the electrical wire
strong along a telephone poles.
 There is a single wire strong between poles.
 No shielding or protection from noise interference is used.
 We are going to extend the traditional definition of open wire
to include any data signal path without shielding or protection
from noise interference.
Application:-
Used in telephones wires.
ii). Twisted pair:
 The wires in twisted pair cabling are twisted together in pair.
 Each pair would consist of a wire used for the positive data
signal & a wire used for the negative data signal.

3.  Any noise that appears on 1 wire of the pair would occur on the
other wire.
Application:-
They are used in telephone lines to provides voice and data
channels.
Local area networks, such as 10 Base-T and Base-T also use
twisted-pair cables.
iii). Coaxial cable:
 Coaxial cable consists of 2 conductors.
 The inner conductors is held inside an insulator with the other
conductor woven around it providing a shield.
 An insulating protective coating called a jacket covers the outer
conductors.
Application:-
It is used in cable networks.
It is used in traditional Ethernet LANs.
iv). Optical fibre:
 Optical fibre consists of thin glass fibres that can carry
information at frequencies in the visible light spectrum and
beyond.
 The typical optical cable fibre consists of a very narrow stand of
glass called the core.
Application:-
The optic fibre cable is often found in backbone networks because
its bandwidth is cost effective.
Used in TV companies.
LAN such as 100 Base-FX Network.

4. B). Unguided media:
 Unguided transmission media is data signals that flow through
the air.
 They are not guided or bound to a channel to follow.
 They are classified by the type of wave propagation;
i). Radio frequency:
o There are 3 types of RF(Radio Frequency) Propogation:
a). Ground Wave propogation.
b). Ionospheric propogation.
c). Line of sight propogation.
a).Ground Wave propogation:
o Ground wave propogation follow the curvature of the earth.
o Ground Wave have carries frequencies up to 2 MHz.
o AM radio is an example of ground wave propogation.
b). Ionospheric propogation:
o Ionospheric propogation bounces off of the earth ionospheric
layer in the upper atmosphere.
o It is sometimes called Double Hop Propogation.
o It operates in the frequency range of 30-85 MHz.
o Ham radio operates in this range.
c). Line of sight propogation:
o Line of sight propogation transmit exactly in the line of sight.
o The receive station must be in the view of the transmit station.
o It is sometimes called space waves or Tropospheric
Propogation.
Application:-

5.  The omnidirectional characteristics of radio waves make
them useful for multicasting, in which there is one sender
but many receivers.
 AM and FM Radio, television, maritime radio, cordless
phone, and paging are examples of multicasting.
ii). Microwave:
 Microwave transmission is line of straight transmission.
 The transmit station must be in visible contact with receive
station.
 This sets a limit on the distance between stations depending on
the local geography.
 Microwave operates at high operating frequencies of 3 to 10
GHz.
 This allows them to carry large quantities of data due to the
large bandwidth.
Application:-
They are used in cellular phones.
They are used in microwave networks.
iii). Satellite:
 Satellite are transponders that are set in a geostationary orbit
directly over the equation.
 A transponder is a unit that receives on one frequency &
retransmits on another.
 The geostationary orbit is 36,000 Km from the earth’s surface.
 The uplink is the transmitter of data to the satellite.
 The footprint is the “Shadow” that the satellite can transmit do.
 The shadow being the areas than can receive the satellite’s
transmitted signal.
Application:-

6. They are used in satellite networks.
They are used in wireless LANs.
5). Conclusion:-
In summary, transmission media are essential for communications
systems.
Signals that carry information can be transmitted on a transmission
medium for communication purposes.
Thus case study on topic transmission media have successfully
completed.