Transmission media

M1-R5.1 & CCC · Chapter 6: Introduction to Internet and WWW · 5 min read

Transmission media

Transmission media is the way in which data is transmitted from one place to another place.
It provide a path way over which the message can trouble from Sender to receiver
Each of the messages can be sent in the form of data by converting them into binary digits.
These binary digits are then coded into a signal that can be transmitted over the app.

1. Guided (Wired) Media

In guided media, signals are transmitted through a physical path such as cables or wires.
The data signals are bounded into the cabling media therefore guided media is also called bounded media.

Types of Guided Media:

Different between Twisted Pair Cable, Coaxial Cable & Fiber Optic Cable

Feature	Twisted Pair Cable	Coaxial Cable	Fiber Optic Cable
Structure	Two insulated copper wires twisted around each other.	Central copper conductor, surrounded by insulation, metallic shield, and outer cover.	Core made of glass or plastic fibers that transmit light signals, surrounded by cladding and protective jacket.
Type of Signal	Electrical signals	Electrical signals	Light (optical) signals
Bandwidth / Data Rate	Up to 10 Gbps	Up to 1 Gbps typically	10 Gbps to several Tbps
Transmission Distance	Up to 100 meters (Ethernet standards)	Up to a few kilometers	Up to 100+ kilometers without signal degradation
Noise / Interference	High susceptibility to EMI (Electromagnetic Interference)	Better noise resistance due to shielding	Immune to EMI and radio frequency interference
Installation & Handling	Easy to install, flexible	Moderate difficulty	Breakable and requires careful handling
Cost	Cheapest	Moderate	Expensive
Common Use	LANs, telephone lines, office networking	Cable TV, CCTV, broadband internet	Backbone networks, long-distance communication, high-speed internet
Security	Easy to tap/intercept	Moderate security	Very secure (hard to tap)
Examples / Types	UTP (Unshielded Twisted Pair), STP (Shielded Twisted Pair)	RG-6, RG-11	Single-mode fiber, Multi-mode fiber

Twisted Pair: Cheap, flexible, best for short-distance LAN connections.
Coaxial Cable: Better shielding and higher bandwidth than twisted pair, used for broadband and TV.
Fiber Optic Cable: Best performance, highest speed, longest distance, and immunity to interference, but costly and delicate.

In unguided media, signals are transmitted through air or space without physical cables.

Different between Radio Waves, Microwaves & Infrared (IR)

Feature	Radio Waves	Microwaves	Infrared Waves
Frequency Range	3 kHz – 300 GHz	300 MHz – 300 GHz	300 GHz – 430 THz
Wavelength Range	100 km – 1 mm	1 m – 1 mm	1 mm – 700 nm
Propagation	Can diffract, reflect, and penetrate buildings easily	Line-of-sight propagation (can be absorbed by rain)	Line-of-sight, easily absorbed by walls and obstacles
Speed	Speed of light (≈ 3 × 10⁸ m/s)	Speed of light	Speed of light
Penetration Ability	Very high; can travel long distances	Moderate; limited by obstacles	Very low; absorbed by most materials
Data Transmission Rate	Low to medium	High	Very high (short range)
Typical Applications	AM/FM radio, TV broadcasting, mobile phones, Wi-Fi (lower bands)	Satellite communication, radar, microwave ovens, Wi-Fi (2.4/5 GHz)	Remote controls, thermal imaging, short-range sensors, fiber optic communication
Antenna Type	Long (dipole or monopole antennas)	Parabolic dishes, horn antennas	IR LED or laser diode emitters
Effect of Weather	Minimal	Affected by rain and humidity	Affected by fog, smoke, and obstacles

Radio Waves: Best for long-distance and broad coverage communication (radio, TV, mobile).
Microwaves: Best for high-speed, medium-distance communication (satellites, radar, Wi-Fi).
Infrared Waves: Best for short-range, high-speed data transmission and sensing (remote controls, IR communication).