Wired Transmission Media

TRANSMISSION MEDIA 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.

TRANSMISSION MEDIA

USE OF TRANSMISSION MEDIA IN COMPUTER

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)

TYPES OF TRANSMISSION MEDIA

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.

TYPES OF TRANSMISSION MEDIA

WIRED TRANSMISSION MEDIA

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.

WIRED TRANSMISSION MEDIA

TYPES OF WIRED TRANSMISSION MEDIA

Wired Transmission Media are of 3 types:-

1. Twisted Pair Cable2. Coaxial Cable3. Optical Fiber Cable

TWISTED PAIR CABLE 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

TWISTED PAIR CABLE

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

TYPES OF TWISTED PAIR CABLE

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).

COAXIAL CABLE

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.

COAXIAL CABLE 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

 

OPTICAL FIBER CABLE 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.

OPTICAL FIBER CABLE 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

OPTICAL FIBER CABLE 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.

THE ADVANTAGES OF WIRED TRANSMISSION MEDIA

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. .

OPERABILITY AND RELIABILITY

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.

COMPATIBILITY 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.

SPEED 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.

SECURITY 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.

CONCLUSION

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