cables

Shree Shankar Narayan Education Trust’s

Shankar Narayan College of Arts, Commerce, B.Sc.I.T. And

B.M.S. And B. & I. & F.

Mahavidyalaya , Bhayander (e) , Thane – 401105.

This to certify that they have satisfactory completed the required things for the

case study of Data Communication System for the topic name as

“Cables(Medium)” for semester II of year 2012-2013 by following members.

AASHU SINGH [111]

SUNIL SOLANKI [113]

VIVEK TIWARI [118]

PAWAN CHATURVEDI [126]

SUMIT MISHRA [139]

And has completed the mentioned work laid down by the in charge of the subject.

Lecturer in charge Head of Department (Prof. Ganesh Narayankar) (Prof. Samita Dalvi)

Date: March 2013 COLLEGE STAMP

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ACKNOWLEDGEMENT APART FROM THE EFFORTS OF ME, THE SUCCESS OF THIS PROJECT DEPENDS LARGELY ON THE ENCOURAGEMENT AND GUIDELINES OF MANY OTHERS. I TAKE THIS OPPORUNITY TO EXPRESS MY GRATITUDE TO THE PEOPLE WHO HAVE BEEN INSTRUMENTAL IN THE COMPLETION OF THIS PROJECT.

I WOULD LIKE TO SHOW MY GREATEST APPERCIATION TO OUR PROF.GANESH NARAYANKAR AND OUR h.O.D Smitha dalvi . I FEEL MOTIVATED AND ENCOURAGED EVERY TIME I ATTEND HIS MEETING. WITHOUT HIS ENCOURAGEMENT AND GUIDANCE THIS PROJECT WOULD NOT HAVE MATERIALIZED.

THE GUIDANCE AND SUPPORT RECEIVED FROM ALL THE TEAM MEMBERS WHO CONTRIBUTED AND ARE CONTRIBUTING TO THIS PROJECT, WAS VITAL FOR THE SUCCESS OF THE PROJECT. I AM GRATEFUL FOR THEIR CONSTANT SUPPORT AND HELP.

Co-axial cables:

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Coaxial cable is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield, surrounded by a tubular plastic jacket.

Coaxial cable was invented by English engineer and mathematician Oliver Heaviside in 1880

Oliver Heaviside

Coaxial cable conducts electrical signal using an inner conductor surrounded by an insulating layer and all enclosed by a shield, typically one to four layers of woven metallic braid and metallic tape.

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The cable is protected by an outer insulating jacket. Normally, the shield is kept at ground potential and a voltage is applied to the center conductor to carry electrical signals.

Coaxial cable design choices affect physical size, frequency performance, and attenuation, power handling capabilities, flexibility, strength, and cost.

The inner conductor might be solid or stranded; stranded is more flexible

To get better high-frequency performance, the inner conductor may

be silver-plated. Copper-plated steel wire is often used as an inner conductor for cable used in the cable TV industry

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The insulating jacket can be made from many materials. But some applications may require fire-resistant materials. Outdoor applications may require the jacket resist ultraviolet light, oxidation and rodent damage. Flooded coaxial cables use a water blocking gel to protect the cable from water infiltration through minor cuts in the jacket

Fig: RF Coaxial Cable Connecter

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Application of Co-axial cables:

It is used in analog telephone networks as well as digital telephone network.

The kind of co-axial cables system used for analog transmission is

used for broadband purpose and the cable used for digital

transmission is used for baseband purpose.

It is used in cable TV.

It is used for digital transmission.

Advantages of co-axial cables:

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One advantage of co-axial cables over other types of radio is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors.

The advantage of coaxial design is that electric and magnetic fields are confined to the dielectric with little leakage outside the shield.

Co-axial cables can support greater cable lengths between network devices than twisted pair cables.

Thick co-axial cables have an extra protective plastic cover that helps in keeping moisture away from the cable.

Sufficient frequency range to support multiple channels.

Low error rate.

Greater spacing can be made between amplifiers as compared to twisted pair cables.

Disadvantages of co-axial cables:

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Signal leakage : Signal leakage is the passage of electromagnetic fields through

the shield of a cable and occurs in both directions. Ingress is the passage of an outside signal into the cable and can result in noise and disruption of the desired signal.

Noise : A noise but unwanted electromagnetic signals which get added

with the original data.

A noise can be manmade like electromagnetic signals, radio waves, radiation etc. Or natural like earthquakes, flood, etc.

Installation : Co-axial cable has thick plastic covering which opposes its

flexibility and make installation difficult. More expensive to install compare to twisted pair cables. Single cable failure can take down an entire network.

Optical Fiber Cables:

Daniel Colladon first described this “light fountain” or “light pipe” in an 1842 article titled” On the reflections of a ray of

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light inside a parabolic liquid stream”. This particular illustration comes from a later article by Colladon, in 1884.

Daniel Colladon

Fig: Daniel Colladon model of light fountain An optical fiber is a flexible, transparent fiber made of glass or

plastic, slightly thicker than a human hair.

It functions as a waveguide. Optical fibers typically include a transparent core surrounded by a

transparent cladding material with a lower index of refraction.

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Light is kept in the core by total internal reflection. This causes the fiber to act as a waveguide.

Fig: Optical Fiber Cables An optical fiber can also be define as an optical fiber is a

cylindrical dielectric waveguide (non-conducting waveguide) that transmits light along its axis, by the process of total internal

reflection

Fig: Demonstration showing Mechanism of Optical Fibers

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Total Internal Reflection: When light traveling in an optically dense medium hits a boundary at a steep angle (larger than the critical angle for the boundary), the light is completely reflected. This is called total internal reflection.

Fig: Total Internal Reflection In simpler terms, there is a maximum angle from the fiber axis at

which light may enter the fiber so that it will propagate, or travel, in the core of the fiber.

Fig: Fiber optics total internal reflection

Types of propagation in optical fiber:

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Single mode propagation: The optical propagation in which only one signal is propagated at a time is called as Single mode propagation.

The diameter of such optical cables is between 8 to 10 microns

Fig: A typical single-mode fiber.

1. Core: 8 µm diameter 2. Cladding: 125 µm dia. 3. Buffer: 250 µm dia. 4. Jacket: 400 µm dia.

Multi-mode propagation: The optical propagation in which no of signals can be sent simultaneously is called as Multi-mode propagation.

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Types of propagation in optical fiber

Single mode propagation

Multi-mode propagation

Diameter of such optical cables is about 50 to 100 microns.

Multiple signal propagation of signals can cause a distortion among the signals and an unclear or incomplete data will be received at receiver end.

Fig: Propagation of light through Multi mode propagation

Advantages of fiber optic cables :

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The size of the optical fiber is very small so a large number of optical fiber can fit into a cable of small diameter.

Optical fiber cable material is easily available so the optical fiber’s cost lower than the metallic conductor cables.

No cross talk inside the optical fiber cable is possible.

Signal can be sent up to hundred times faster.

Installation process is easy as fibber optic’s cable is flexible.

Repeaters are not required as the transmission losses in the fiber optics are low.

Since the transmission take place in the form of light rays the signal is not affected by an electrical or electromagnetic interference.

Greatly increased Bandwidth and capacity.

Less restrictive in harsh environments.

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Disadvantages of Optical fiber cables : Sophisticated plants are required for manufacturing of optical

fiber.

The initial price of optical fiber is very high.

Joining optical fiber is a difficult task.

Optical fiber needs proper polishing for proper propagation of light

Fiber optic components are expensive

Twisted pair cables:

Twisted pair cabling is a type of wiring in which two conductors of a single circuit are twisted together.

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Twisted pair cables

The twisting is made in the form of Helical like DNA model. For the purposes of canceling out electromagnetic interference

(EMI) from external sources.

Twisted pair cables were invented by “Alexander Graham Bell”

in 1881.

Fig: Twisted pair cables

Twisted pair cables can run to several kilometers with amplifications. But for longer distance repeaters are needed due to which it

remains for years. It can be used for both Analog and Digital signal. The Bandwidth required, depends on the thickness of wire and

distance travelled.

Types of Twisted pair cables :

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Depending upon the coating give to each pair of the cable ,the twisted pair is divided into 2 types as follows :

1) Shielded twisted pair.

2) Un-shielded twisted pair.

Shielded twisted pair (STP):

STP has a metal foil covering to each insulating conductors. The STP was developed by IBM. STP cables are often used in an attempt to prevent electromagnetic

interference.17

As the shielding is made of metal, it may also use for a ground. Shielding provides conduction path by which currents can be

circulated and returned to the source, via ground reference connection.

Fig: Shielded twisted pair.

STP cabling is used in network especially for fast data rate. Shielding protects cable from external EMI from entering or exiting

the cable. It also protects neighboring pairs from crosstalk. As it requires extra covering it is little expensive then UTP. As it offers better noise resistance, it can be used in MAN, WAN

network.

Un-shielded twisted pair (UTP): UTP does not have any metal foil covering to its insulating

conductors.

UTP provides bad resistance towards the electromagnetic interference.

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No grounding is possible in UTP as it does not have any extra metal conductor or covering.

Fig: Un-shielded twisted pair. Installation does not require any special attention. It is cheap as compared to STP. Distance covering may be less as it provides bad resistance to

electromagnetic interference and noise. Due to same reason it also offers less Bandwidth. UTP cable is also the most common cable used in computer

networking. It is mostly used in local area networking. The standard connecter for UTP is RJ-45.

Distinguish between STP and UTP:

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Shielded Twisted Pair Un-shielded Twisted Pair

1. STP has a metal foil covering. 1. UTP does not have a metal foil

Covering.

Applications of Twisted pair cables:

It is used in telephone line to carry voice and data channel.

As it is least expensive , it is used in Local area network(LAN) It can be used, where multiple connections is needed, as it can carry

number of twisted pair. They are used is CAT 5 (Category 5) types of cablings.

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1. UTP does not have a metal foil

Covering.

2. STP gives better resistance to electromagnetic interference as compared to UTP.

2. UTP does not provide better resistance to electromagnetic interference as compared to STP.

3. UTP is less expensive than STP.

3. STP is little expensive then UTP.

4. Grounding is possible. 4. Grounding is not possible.

5. Possibility of crosstalk is less as it resist to EMI.

5. Possibility of crosstalk is more as it provide less resistance to EMI.

6. Distance travelled is less and used in LAN.

6. Distance travelled is large and can be used in MAN.

There 5 level of data cabling : Category 1

These are used in telephone lines and low speed data cable.

Category 2

These cables can support up to 4 mps implementation.

Category 3

These cable supports up to 16 mps and are mostly used in 10 mps.

Category 4

These are used for large distance and high speed. It can support 20 mps.

Category 5 This is the highest rating for UTP cable and can support up to 100mps

Advantages of twisted pair cables:

It is a thin, flexible cable that is easy to string between walls.

More lines can be run through the same wiring ducts.

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Electrical noise going into or coming from the cable can be prevented.

Cross-talk is minimized.

It can transfer a data with the speed of about 100mbps.

They cost less than any other networking cables.

Installation of twisted pair cables is easy.

As it is flexible it can cover a long distance.

It can remain in work for long years.

These are the fastest copper-based medium available.

Disadvantages of twisted pair cables:

A signaling delay may be experienced.

Difficult to connect at terminal, as it has number of wires in it.22

As the distance increases the transmission rate decreases.

More susceptible to interference or noise.

Introduction:

Mineral-insulated copper-clad cable is a variety of electrical cable made from copper conductors inside a copper sheath, insulated by inorganic magnesium oxide powder.

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MI cable is made by placing copper rods inside a circular copper tube

and filling the intervening spaces with dry magnesium oxide powder.

Fig: Mineral-insulated copper-clad cable

Up to seven conductors are often found in an MI cable, with up to

19 available from some manufacturers. MI cables may be covered with a plastic sheath, coloured for

identification purposes.

History:

The first patent for MI cable was issued to the Swiss inventor

Arnold Francois Borel in 1896.

Arnold Francois Borel

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Also the materials like Pulverized glass, silicious stones, or asbestos, in powdered form, where patented.

Commercial production began in 1932.

In 1937 a British company “Pyrotenax”, having purchased patent rights to the product from the French company.

During the Second World War much of the company's product was used in military equipment.

In 1964, the Pyrotenax introduced the aluminum sheathed version of the same cable.

This type of cables is also known as “Pyro” because the first company to introduce this cable is Pyrotenax.

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Application of Mineral-insulated copper-clad cable:

It is used in nuclear reactor.

It is also used in hospital operating rooms. In Fire alarm systems. In emergency system like power systems and lighting systems. In Temperature measurement devices like RTD's and

Thermocouples. Critical process valves in the petrochemical industry.

Public buildings such as theatres, cinemas, hotels. Transport hubs (railway stations, airports etc.) In Tunnels and mines. Electrical equipment in hazardous areas where flammable

gases may be present e.g. oil refineries, petrol stations. Areas where corrosive chemicals may be present e.g. factories. Hot areas e.g. power stations.

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Advantages of Mineral-insulated copper-clad cable :

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