Twisted-pair cable, coaxial cable, and fiber-optic cable are guided media that provide a conduit for transmission. Twisted-pair cable reduces noise through regular twisting of the wire pairs. Unshielded twisted-pair (UTP) cable is commonly used for telephone and Ethernet connections while shielded twisted-pair (STP) provides better noise shielding but is more expensive. Coaxial cable uses a central conductor surrounded by insulating and outer conducting layers to carry higher frequency signals than twisted pair over longer distances.

1. Transmission Media
Presented by:-
Abhishek Wadhwa
Arvind Lal Dass
Nitin Malhotra

2. Classes of transmission media

3. Transmission Media
Guided Media
Guided media, which are those that provide a
conduit from one device to another, include twisted-
pair cable, coaxial cable, and fiber-optic cable.
Topics discussed in this section:
Twisted-Pair Cable
Coaxial Cable

4. Twisted-pair Cable
• The number of twist per unit length has the effect on the
quality of the cable.

6. How Twisted-Pair Cable Reduces Noise
Interference from devices such as a motor can
create unequal noise over two parallel lines.
The line that is closer to the device receives
more interference than the one that is farther.
If however, the wires are twisted around each other at regular
intervals, each wire is closer to the noise source for half of the
time and farther for the other half.
Both receive the same amount of noise. The noise from two wires
cancel each other out at the receiver.

7. UTP and STP cables
Unshielded twisted-pair Shielded twisted-pair

8. Unshielded Twisted Pair (UTP)

9. UTP
Contd..
Consists of 4 pairs (8 wires) of insulated
copper wires typically about 1 mm
thick.
The wires are twisted together in a
helical form.
Twisting reduces the interference
between pairs of wires.
High bandwidth.
Flexible and cheap cable.

10. Categories of UTP
UTP comes in several categories that are based on the
number of twists in the wires, the diameter of the wires and
the material used in the wires.
CAT 1,CAT 2,CAT 3, CAT 4, CAT 5, Enhanced CAT 5 ,CAT 6,
and now CAT 7.
Category 3 is the wiring used primarily for telephone
connections.
Category 5e and Category 6 are currently the most common
Ethernet cables used.

12. UTP performance

13. Connecting your Device through UTP
Materials Required:
*UTP cable:
*RJ-45 Connector:
(Register jack)
*Crimper Tool:

14. Connecting your Device through UTP
T-568A Standard:

18. Applications
Twisted-pair cables are used in telephone lines to provide
voice and data channels.
The local loop (the line that connects subscribers to the
central telephone office) commonly consists of unshielded
twisted-pair cables.
The DSL(Digital Subscriber Line) lines that are used by the
telephone companies to provide high-data-rate connections.
High-bandwidth capability of unshielded twisted-pair cables is
used in LAN connections.

19. Shielded Twisted Pair (STP)

20. IBM produced another version of
twisted pair cable and that is STP which
has a metal foil covering that encases
each pair of insulated conductors or
wires in pair.

21. What it is and what it do
• STP cable combines the techniques of
shielding,cancellation and wire twisting.
• Each pair of wires is wrapped in a metallic foil.
• The five pairs then wrapped in an overall metallic
foil.
• STP reduces electrical noise both from
a. Within the cable(Pair to pair coupling)
b. Outside the cable.

22. • In addition the metallic shielding must be
grounded at both ends of the cable.
• If it is improperly grounded the shield
acts like an antenna which can pick
signals not needed.
• It rarely comes in actual use because of
its cost and difficult to terminate.

23. Important points
• SPEED – 10 to 100MBPS(1000)
• Average cost per node – Expensive than
UTP
• Media connector size – Medium to
large(S-L)
• Maximum cable length – 100m

24. Difference
When comparing UTP and STP we should know
that:
These are the least expensive media for data
communication but if we do a comparison of
these both then we must know that UTP is
less expensive than the STP.

25. Contd..
And because most buildings are already
wired with the UTP many transmission
standards are adapted to use it to avoid
costly rewiring with an alternative cable
type like STP.

26. Few things we should know about STP
STP cable is developed by IBM
for token ring that consists of
two individual wires wrapped in a
foil shielding to help provide a
more reliable data connection.

27. Contd..
Token ring-A network where all computers on
the network are connected in a circle fashion.
The term token is used to describe a segment
of information that is sent through that circle;
when a computer on the network is able to
decode that token, the information is received
on that computer.

28. Contd..
• It is a type of wiring in which each of the two
wires that are twisted together are coated
with an insulating coating.
• The extra covering in shielded twisted pair
wiring protects the transmission line from
electromagnetic interference.

29. Co-axial Cable

31. Coax
Coax carries signals of higher frequency ranges (higher
Bandwidth) than twisted pair.
Inner conductor carries signal.
Outer one serves as shield against noise and as the second
conductor, which completes the circuit).

32. Contd…
Instead of having two wires, coax has a central core
conductor of solid or stranded wire (usually
copper) enclosed in an insulating sheath, which is, in
turn, encased in an outer conductor of metal foil, braid,
or a combination of the two.
The outer metallic wrapping serves both as a shield against
noise and as the second conductor, which completes the
circuit.
This outer conductor is also enclosed in an insulating
sheath, and the whole cable is protected by a plastic
cover.

33. General Rules for Coax
D = diameter of insulation under the shield.
d = diameter of inner conductor.
Attenuation or Loss
Raising the D/d ratio
lowers attenuation

34. Categories of Coax
Coax is categorized by Radio Government (RG) rating.
Each RG number denotes a unique set of physical spec.
(wire gauge of inner conductor, thickness and type of
inner insulator, etc.).

35. Categories:
Two kinds:
 Thicknet (RG-11): It connect 100 devices with
range 500m (more expensive ).
Thinnet (RG-58): It connect 30 devices within
185 m (cheaper).

36. BNC connectors
To connect coaxial cable to device, we need BNC.
Bayone-Neill-Concelman connector is the most common type.
• BNC connector is used to connect the end of cable to a device.
• BNC T connector is used to branch out the connection.
• BNC terminator is used at the end of the cable to prevent reflection of the signal.

37. Coaxial cable performance
**Coax has higher BW but the attenuation is also higher than twisted pair
cable.
** Requires frequent use of repeaters.

38. Coaxial Cable Applications
Most versatile medium
Television distribution
 Ariel to TV
 Cable TV
Long distance telephone transmission
Can carry 10,000 voice calls simultaneously
Being replaced by fiber optic
Short distance computer systems links
Local area networks

39. Any
Questions?

40. Thank you
Download it
from:www.programming90.blogspot.com