This document discusses different types of guided media used for data transmission. It describes twisted pair cable, coaxial cable, and fiber-optic cable. Twisted pair cable uses two insulated copper wires twisted together to reduce interference. Coaxial cable contains a central conductor surrounded by insulation and shielding to carry higher frequency signals. Fiber-optic cable uses glass or plastic strands to transmit data via light reflection down the core of the cable. The document provides diagrams of the cable structures and components.

1. GUIDED MEDIA
Presented by
Shakhawat Amin
Reg. : 2012331009
Dept : Computer Science and Engineering, SUST
Acknowledgement
Mrs. Sadia Sultana
Assistant professor, CSE, SUST
Mr. Refat Kibria
Assistant professor, CSE, SUST

2. What is a transmission media ?
 Transmission Media is a pathway that carries information from
sender to receiver.
 Transmission Media are located below Physical layer and
directly controlled by physical layer.

3. Classification
Data is normally transmitted through electrical or electromagnetic
signals through transmission medium.
Transmission media can be categorized by whether it uses physical
path or not.

4. GUIDED MEDIA
In a transmission media if electrical or electromagnetic waves are
guided along a physical path then it is called Guided media.

5. Twisted pair Cable
 A twisted pair consists of two conductors (normally copper), each
with its own plastic insulation, twisted together.
 One of the wires is used to carry signals to the receiver, and the
other is used only as a ground reference.

6. Provide protection against crosstalk and
interference (noise).
For twisting after receiving the signal remains
same.

7. fig: Unshielded twisted pair cable fig: Shielded twisted pair cable

8. Coaxial Cable
Coaxial cable (or coax) carries signals of higher frequency
ranges than those in twisted pair cable. Instead of having two
wires, coax has a central core conductor of solid or stranded
wire.
The outer metallic wrapping serves both as a shield against
noise and as the second conductor, which completes the
circuit.

9. fig: Coaxial cable

10. To connect coaxial cable to devices, we need coaxial
connectors.
The most common type of connector used today is the
Bayone – Neill - Concelman (BNC) connector.
Coaxial Cable
Connectors

11. fig: BNC connectors
three popular types of BNC connectors:
i. The BNC connector (used to connect the end of the
cable to a device)
ii. The BNC T connector (used in Ethernet network to
branch out to a connection to a computer)
iii. The BNC terminator (used to prevent the reflection
of the signal)

12. fig: BNC connectors

13. Fiber-Optic Cable
A fiber-optic cable is made of glass or plastic and transmits
signals in the form of light.
fig: Optical Fiber Cables

14. To understand optical fiber, we first need
to explore several aspects of the nature
of light.
Light travels in a straight line as long as it
is moving through a single uniform
substance.
If a ray of light traveling through one
substance suddenly enters another
substance the ray changes direction.

15. fig: Bending of light ray

16. Fig: Optical fiber
Optical fibers use reflection to guide light through a channel. A
glass or plastic core is surrounded by a cladding of less dense
glass or plastic. The difference in density of the two materials
must be such that a beam of light moving through the core is
reflected off the cladding instead of being refract into it.

17. Two modes (multimode and single mode) for
propagating light along optical channels, each
requiring fiber with different physical characteristics.
Multimode can be implemented in two forms:
 step-index fiber &
 graded-index.
PROPAGATION MODES

18. Fig : Propagation modes

19. fig: Fiber Construction

20. THE END