Presentation on Transmission medium presented by me and my friend in college competition.

2.  What is transmission media?
Pathway that carries the information from sender to receiver.
 What is used for transmitting data?
We use different types of cables or waves to transmit data.
Data is transmitted normally through electrical or
electromagnetic signals.
INTRODUCTION

3. Types of transmission media

4.  Bounded transmission means having connectivity between a source and
destination using cables or wires.
 The signals have to travel through this channel i.e. physical media and
this makes it limited to its expansion. (One cannot run a cable 100 kms
long)
 It is more reliable and fast in quality of data transmission compared to
wireless.
 Types of Wired Transmission media:
1. Twisted Pair Cable
2. Coaxial Cable
3. Optical Fiber Cable
I. Wired or Guided Transmission media

5. 1. Twisted Pair Cables
 The most popular network cabling is Twisted pair.
 It is light weight, easy to install, inexpensive and support many different
types of network.
 It also supports the speed of 100 mps.
 Twisted pair cabling is made of pairs of solid or stranded copper twisted
along each other.
 The twists are done to reduce vulnerably to EMI and cross talk.
 The number of pairs in the cable depends on the type.

6. There are Two type of twisted pair cable:
a. Unshielded Twisted Pair (UTP) cable:
- Used for variety of electronic
communication.
- UTP cable can have maximum segment
length of 100 meters.
b. Shielded Twisted Pair (STP) cable:
- Protection from crosstalk when used in
phones.
- Can have maximum length of 100
meters.

7.  Coaxial cable is very common & widely
used commutation media. For example
TV wire is usually coaxial.
 The core or the inner portion of the
coaxial is made of copper. There is a
plastic type non-conductive cover over
the central core (copper wire). The outer
most cover is of copper mesh which is
very fine and is used to avoid any EMI
(Electromagnetic Interference) on the
cable. The middle plastic cover
separates the inner copper conductor
from the outer copper mesh. And
covering the entire wire is another
protective cover or jacket.
 The copper conductor in the center is
responsible for data transfer whereas the
outer mesh prevents EMI.
2. Coaxial Cables

8.  Optical fiber consist of thin strands of glass or glass
like material.
 The light sources (LEDs or LDs) are used to
transmit data. A laser at one device sends pulse of
light through this cable to other device. These
pulses translated into “1’s” and “0’s” at the other
end.
 Fiber optic cable has bandwidth more than 2 gbps
(Gigabytes per Second)
 Advantages:
1. Fast
2. Low attenuation
3. No EMI interference
 Major Drawbacks:
1. Hard to install
2. Very expensive
3. Optical Fiber Cables

9. II. Wireless or Unguided Transmission media
 Unbound transmission media are the ways of transmitting data without using
any cables.
 Frequencies in the range of about 1GHz to 40GHz are referred to as
microwave frequencies. At these frequencies, highly directional beams are
possible and microwave is quite suitable for point to point transmission.
Microwave is also used for satellite communication.
 Frequencies in the range of 30MHz to 1GHz are suitable for Omni-directional
applications. This range is referred to as Radio Range.
 Another important frequency range, for local application, is the infrared
portion of the spectrum. This covers, roughly from 3*1011 to 2*1014 Hz.
Infrared is useful to local point to point and multipoint application within
confined areas, such as single room.

10. 1. Radio waves
 Radio waves can operate on a single or multiple frequency bands.
 Radio waves are omni directional i.e. they travel in all the directions from the
source. Because of this property, transmitter and receiver need not to be
aligned.
 Radio waves can penetrate buildings easily, so they are widely use for
communication both indoors outdoors.
 At high frequencies, radio waves tends to travel in straight line and bounce off
the obstacles.
 They are also absorbed by rain.
 Radio waves are widely used for AM and FM radio, television, cordless
telephone, cellular phones, paging and wireless LAN.

11. 2. Microwave Transmission
 Microwaves have been used in data communications for a long time. They
have a higher frequency than radio waves and therefore can handle larger
amounts of data.
 Microwave transmission is line of sight transmission. The transmit station
must be in visible contact with the receive station. This sets a limit on the
distance between stations depending on the local geography. Typically the
line of sight due to the Earth's curvature is only 50 km to the horizon!
Repeater stations must be placed so the data signal can hop, skip and jump
across the country. microwave circuits considered a broad band
communication channel.
 Microwaves operate at high operating frequencies of 3 to 10 GHz. This
allows them to carry large quantities of data due to their large bandwidth.

12. 3. Infrared
 Infrared offers a great unbound photonic solution. Like fiber-optic
cabling, infrared communications use light, so they are not bound by the
limitations of electricity.
 This type of transmission uses infrared light to send the data.
 The infrared light transmit data through a air and can propagate throughout the
room but will not penetrate walls.
 This communication is allowed in IBM company and data is communicated
easily from source to destination.

13. 4. Bluetooth
 A short range wireless technology. Operate at approx. 1Mbps with range from
10 to 100 meters. Bluetooth is an open wireless protocol for data exchange over
short distances.

14. 5. Satellite
 Uses microwave radio to prevent from atmosphere and act as microwave relay
station.
 They are situated in space 22,000 miles above the equator.
 It appears stationary from the earth as it rotates with specific speed.
 They can amplify and relay microwave signals from one transmitter on the
ground to another.
 Capable of receiving, relaying of voice, data, and TV signals.
 Bad weather can affect the communication.

15. From -
Surabhi M V
Sharanya R