1.  Guided Media: 

Guided transmission media are physical pathways or channels that guide electromagnetic signals along a specific path. These mediums provide a physical conductor to carry signals between devices. Here are some common types of guided transmission media:

• Twisted Pair Cable: Consists of pairs of insulated copper wires twisted together to reduce electromagnetic interference. Twisted pair cables are widely used in telephone lines and Ethernet networks for data transmission over short to medium distances.
• Coaxial Cable: Consists of a central conductor surrounded by a dielectric insulator and an outer metallic shield. Coaxial cables provide better shielding and higher bandwidth compared to twisted pair cables. They are commonly used in cable television (CATV) networks, broadband internet connections, and high-speed data networks.
• Optical Fiber: Utilizes light signals transmitted through glass or plastic fibers to carry data. Optical fibers offer high bandwidth, immunity to electromagnetic interference, and long-distance transmission capabilities. They are widely used in telecommunications networks, internet backbone infrastructure, and high-speed data connections.

Guided transmission media offer advantages such as reliability, security, and higher data transfer rates compared to wireless transmission media. However, they are typically limited by factors such as distance, installation complexity, and susceptibility to physical damage. The choice of guided transmission media depends on factors such as the required data transfer rate, distance, cost, and environmental considerations.

2. Unguided Media:

Unguided transmission media, also known as wireless communication channels, are mediums through which electromagnetic signals propagate through free space without the use of physical conductors. Here are some common types of unguided transmission media:

• Radio Waves: Radio waves are electromagnetic waves with wavelengths ranging from several millimeters to kilometers. They are used for various wireless communication applications, including radio broadcasting, two-way radio communication, and wireless networking (Wi-Fi).
• Microwaves: Microwaves are electromagnetic waves with wavelengths ranging from one meter to one millimeter. They are commonly used in point-to-point communication links, satellite communication, microwave ovens, and radar systems.
• Infrared Waves: Infrared waves are electromagnetic waves with wavelengths longer than visible light but shorter than microwaves. They are used for short-range wireless communication in devices such as remote controls, infrared data transmission (IrDA), and proximity sensors.
• Light Waves (Visible and Ultraviolet): Light waves, including visible light and ultraviolet (UV) light, can be used for wireless communication in optical wireless communication (OWC) systems. Light waves are modulated to transmit data, and receivers decode the light signals to recover the transmitted information. Applications include free-space optical communication (FSO), Li-Fi (Light Fidelity), and underwater optical communication.

Unguided transmission media offer several advantages, including the ability to transmit data over long distances without the need for physical cables, flexibility in deployment, and mobility for users or devices. However, they are susceptible to interference from environmental factors such as obstacles, atmospheric conditions, and electromagnetic interference (EMI). Additionally, unguided transmission media may have limitations in terms of data transfer rates and security compared to guided transmission media.