Question

What are the classification of transmission media?

Answer 1

Transmission media can be classified based on the type of physical medium they use to carry signals. There are two main categories: guided media and unguided media.

1. Guided Media (Wired or Bounded Media)

Guided media refers to transmission media where the signals are transmitted through a physical pathway, like cables or fibers. The data travels through these mediums with specific paths.

1. Twisted Pair Cable:
   

  - Consists of pairs of insulated copper wires twisted together.
  - Unshielded Twisted Pair (UTP): Common in telephone lines and Ethernet networks.
  - Shielded Twisted Pair (STP): Has additional shielding to reduce interference and noise.

1. Coaxial Cable:
   

  - Consists of a central copper conductor, an insulating layer, a metallic shield, and an outer insulating layer.
  - Commonly used for cable TV, internet, and networking applications.

1. Fiber Optic Cable:
   

  - Uses light to transmit data through glass or plastic fibers.
  - Single-mode fiber: Transmits data in a single path, used for long-distance communication.
  - Multi-mode fiber: Transmits multiple signals in different paths, used for shorter distances.

2. Unguided Media (Wireless or Unbounded Media)

Unguided media refers to transmission through the air, without the need for physical cables or wires. These use electromagnetic waves (radio waves, microwaves, etc.) to send signals.

1. Radio Waves:
   

  - Used for long-distance communication, including AM/FM radio, TV broadcasts, and wireless networking.
  - Can travel through the air and around obstacles.

1. Microwaves:
   

  - Higher frequency than radio waves, used for point-to-point communication, such as satellite communications and long-distance mobile networks.
  - Requires line-of-sight between transmitting and receiving stations.

1. Infrared (IR):
   

  - Uses light waves in the infrared spectrum.
  - Common in remote controls, short-range communication (like Bluetooth), and some wireless devices.

1. Satellite Communication:
   

  - Relies on microwaves sent to and received from satellites in orbit.
  - Used for TV broadcasts, internet access, and global communications.

1. Visible Light Communication (VLC):
   

  - Uses visible light for data transmission, such as through LED lights.
  - An emerging technology for high-speed wireless communication (e.g., Li-Fi).

Summary:

1. Guided media: Twisted pair, coaxial cables, fiber optics (data travels through physical cables).
   

1. Unguided media: Radio waves, microwaves, infrared, satellite, VLC (data travels through the air).
   

Each type of media has its own set of advantages and is chosen based on factors like distance, bandwidth, and environmental conditions.