Wired Transmission Media

1. Wired
Transmission
Media

2.  Transmission media is simply the means through
which data is transformed from one place to
another. OR
 Transmission media is a pathway that carries the
information from sender to receiver.
 This could be through wire, fiber optics, vacuum
or coaxial cable.
 We use different types of cables or waves to
transmit data. Data is transmitted normally through
electrical or electromagnetic signals.
 Transmission media is also called
Communication channel.

4.  Transmission media play a very important role in
computer network.
 In computer networking it is used to transfer
resources(like data /information) from one place to
another.
 Transmission capacity (in terms of bandwidth and
data rate) depends on distance and type of network
(point to point or multi point)

5.  Transmission media is broadly classified into two
groups:
 1. Wired or Guided Media or Bound
Transmission Media.
 2. Wireless or Unguided Media or Unbound
Transmission Media.

7.  Wired transmission media is also called as
physical media or guided media.
 In wired transmission media, one network is
connected to another network using a set of wires.
 Wired transmission media provide physically
constrained signal propagation.
 In contrast, Wireless transmission media provide
unconstrained signal propagation.

9. Wired Transmission Media are of
3 types:-
1. Twisted Pair Cable
2. Coaxial Cable
3. Optical Fiber Cable

10.  Twisted Pair Cable is very common in our daily
life,even a phone wire is also made up of Twisted Pair
Cables.
 It consist 8 wires and 4 pairs(2 each).
 Very cheap technology as compared to Fiber Optic
cable and Coaxial cable.
 Twisting reduces interference
 Twisting decreases the crosstalk interference
 Twist length varies from 5 to 15 cm
 Wires in pairs have thicknesses from 0.4 to 0.9 mm

11. Application :
 Most common transmission media for both digital and
analog signals
 Less expensive compared to coaxial cable or optical fiber
 Limited in terms of data rate and distance
 Used for telephone network
 Used for communication within buildings which allows data
rate of 64 kbps
Transmission Characteristics:
 Used to transmit both analog and digital signal
 Requires amplifiers every 5-6 km for analog signal
 Requires repeaters every 2-3 km for digital signal

12. UTP
 UTP stands for Unshielded Twisted Pair cable.
 It is effected by EMI(Electro Magnetic Interference).
STP
• STP stands for shielded Twisted Pair cable.
• It is not effected by EMI(Electro Magnetic Interference).

13.  Consists of two conductors separated by insulation
 Hollow outer cylindrical conductor surrounding a single inner
wire conductor
 Outer conductor covered with a jacket or shield
 Diameter from 1 to 2.5 cm
 Shielded concentric construction reduces interference and
crosstalk
 Can be used over longer distances and support more stations on a
shared line than twisted pair
 Carry more data as compared to Twisted Pair Cable.
 Coaxial Cable again divided into two parts:-
1.Thin cable:-Only one signal transmit at a time.
2.Thick cable:-More than one signal transmit at a time.

14. Application :
 Most common use is in cable TV
 Traditionally part of long distance telephone network
 Can carry more than 10,000 voice channels simultaneously using
frequency-division multiplexing
 Short range connections between devices
Transmission Characteristics:
 Used to transmit both analog and digital signals
 Superior frequency characteristics compared to twisted pair
 Can support higher frequencies and data rates
 Shielded concentric construction makes it less susceptible to interference
and crosstalk than twisted pair
 Requires amplfiers every few kilometers for long distance transmission
 Requires repeaters every few kilometers for digital transmission

15.  It provide better and fast communication as compared
to Twisted pair cable and coaxial cable.
 It transfer data at very high speed through light signal.
 Thin ,flexible material to guide optical rays
 Cylindrical cross section with three concentric links
1.core
2.cladding
3.jacket
 Optical rays travel in glass or plastic core
 Optical Fiber Cable is again divided into two parts:-
1.Single mode Optical Fiber Cable:-One light signal
transmit at a time.
2. Multi mode Optical Fiber Cable:-More than one
light signal transmit at a time.

16. Application
 Long haul trunks:
Increasingly common in telephone networks
About 1500km in length with high capacity (20000 to 60000
voice channels)
 Metropolitan trunks:
Average length of about 12 km with a capacity of 100,000 voice
channels
Mostly repeaterless to join phone exchanges in metro areas
 Rural exchange trunks:
Circuit lengths from 40 to 160 km
Fewer than 5000 voice channels
Connect exchanges of different phone companies
 Subscriber loops:
Central exchange to subscriber
May be able to handle image and video in addition to voice and data
 Local area networks:
100Mbps to 1Gbps capacity
Can support hundreds of stations on a campus

17. Transmission Characteristics:
 Based on total internal reflection
 For this to take place-
- light has to travel from rarer to denser medium. Hence in
optical fibre the core is rarer as compared to cladding
 Since, optical fiber propagetes light a device is needed to convert
electric signal pulses to light wave of different wavelength. This is
achieved by using WDM (wavelength division multiplexing ) and
LASER is usually used for the propagation.
 Optical fiber transmission are of 3 modes:-
1. step index multimode
2. step index single mode
3. graded index multimode
 Among these 3 step index single mode is used for transmission.

19.  Wireless networks have some disadvantages that
wired networks easily overcome.
 Wireless technology has become part of everyday
life. Everything, from phones and satellites, to
computer equipment and the Internet, no longer
requires long, bulky wires to work properly.
 However, many wireless forms of transmission
media have shortcomings when compared to wired
transmission media. In instances where reliability,
compatibility and security are necessary, it can be
advantageous to have wired networks. .

20.  Sometimes wireless devices don't work as well as
they should.
 They can experience interference, fluctuations in
bandwidth and instability from the weather.
 Wired networks experience little interference and
rarely have disruptions due to inclement weather.
 In the case of a wireless home alarm, the system can
experience radio frequency interference and distance
limitations, whereas wired alarm systems can
transmit without nearly as much interference, making
distance almost a moot point.

21.  Many older computer systems are not compatible with
wireless technology.
 They require extra hardware, such as a Bluetooth adapter,
to use a limited range of wireless devices.
 Even then, some older operating systems are not
compatible with wireless transmission media at all.
 Wired data transmission, on the other hand, is highly
compatible with both older cell phones and computers,
using everything from phone lines to USB or Ethernet
cables to transmit data from system to system.
 With the right hardware, it's possible to connect more
devices to one another using wired means than with
wireless.

22.  Wireless networks and other transmission media have
made gains in speed and reliability, but they pale in
comparison to the speed that wired networks can
provide.
 DSL Internet access, for instance, will transmit data far
faster than a wireless Internet connection.
 Wireless connections often suffer from interference and
weaker signals, depending on location, affecting the
speed of data transmission.
 Wired connections overcome both quite easily without
any loss in speed.

23.  Wireless networks tend to suffer from more security
attacks than wired networks.
 In a wired network, a hacker would have difficulty
walking into a home or business and tampering with
the wires.
 However, in a wireless network, a hacker only needs
to have close proximity and a knowledge of how
wireless data transmission works to get inside.
 A hacker can simply use a vulnerable wireless
connection to surf the net, or he may steal personal
data stored on a computer within the network.
 He also will have an easier time intercepting data sent
wirelessly than data sent through a wired connection.

25. Hence, Wired transmission
Media is used for data
transmission in our life and in
this modern world.