Different Types of Transmission Mediums

Data is represented by computers and other telecommunication devices using signals. Signals are transmitted in the form of electromagnetic energy from one device to another. Electromagnetic signals travel through vacuum, air or other transmission mediums to move from one point to another(from sender to receiver).

Electromagnetic energy (includes electrical and magnetic fields) consists of power, voice, visible light, radio waves, ultraviolet light, gamma rays etc.

Transmission medium is the means through which we send our data from one place to another. The first layer (physical layer) of Communication Networks OSI Seven layer model is dedicated to the transmission media, we will study the OSI Model later.

Wired or Bounded Transmission Mediums

Wired or the bounded transmission mediums use physical cables to transmit data. The key types are:

1. Twisted Pair Cable

• Description: Consists of pairs of insulated copper wires twisted together.

• Types:

  • Unshielded Twisted Pair (UTP): Common in Ethernet networks. Vulnerable to electromagnetic interference (EMI).

  • Shielded Twisted Pair (STP): Has a protective shield to reduce EMI. Used in environments with high interference.

• Speed & Distance: Supports speeds up to 10 Gbps over short distances (up to 100 meters for Cat6a cables).

• Applications: Local Area Networks (LANs), telecommunication networks.

2. Coaxial Cable

• Description: A single copper conductor at the center, surrounded by insulation, a metallic shield, and an outer insulating layer.

• Speed & Distance: Can support speeds up to 10 Gbps and distances up to 500 meters.

• Applications: Cable television networks, early Ethernet networks (10BASE2, 10BASE5).

3. Fiber Optic Cable

• Description: Uses light pulses to transmit data through strands of glass or plastic fibers.

• Types:

  • Single-mode Fiber (SMF): Has a small core, supports long-distance communication (up to 100 km).

  • Multi-mode Fiber (MMF): Has a larger core, supports shorter distances (up to 2 km).

• Speed & Distance: Supports very high speeds (up to 100 Gbps) over long distances.

• Applications: Backbone networks, high-speed internet connections, long-distance telecommunications.

Wireless or Unbounded Transmission Mediums

Wireless or Unbounded transmission mediums use electromagnetic waves to transmit data without physical cables. The key types are:

1. Radio Waves

• Description: Uses radio frequencies (RF) to transmit data over the air.

• Range: Can vary from a few meters (Bluetooth) to several kilometers (Wi-Fi, cellular networks).

• Applications: Wi-Fi, cellular networks (2G, 3G, 4G, 5G), Bluetooth.

2. Microwaves

• Description: Uses high-frequency radio waves (1 GHz to 300 GHz) for point-to-point communication.

• Range: Supports long-distance communication with line-of-sight transmission.

• Applications: Satellite communication, point-to-point links, microwave ovens.

3. Infrared (IR)

• Description: Uses infrared light to transmit data over short distances.

• Range: Limited to line-of-sight and short distances (a few meters).

• Applications: Remote controls, short-range communication between devices (like infrared ports on laptops).

4. Satellite Communication

• Description: Uses satellites in space to relay data between ground stations.

• Range: Global coverage, ideal for long-distance and remote area communication.

• Applications: Global Positioning Systems (GPS), satellite internet, television broadcasting.

Factors to be considered while selecting a Transmission Medium

1. Transmission Rate
2. Cost and Ease of Installation
3. Resistance to Environmental Conditions
4. Distances
5. Security of the Network