Lesson Notes By Weeks and Term v4 - SHS 3
GUIDED AND UNGUIDED NETWORK SYSTEMS
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
GUIDED AND UNGUIDED NETWORK SYSTEMS
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Ict
Class: SHS 3
Term: 2nd Term
Week: 13
Grade code: 3.2.1.LI.1
Strand code: 2
Sub-strand code: 1
Content standard code: 3.1.2.CS.1
Indicator code: 3.2.1.LI.1
Theme: NET WORK SYSTEMS FOR TRANSMI TTING INFORMATION
Subtheme: GUIDED AND UNGUIDED NETWORK SYSTEMS
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
In our daily lives in Ghana, we are constantly connected. We use WhatsApp to chat with family, watch videos on YouTube, check WASSCE results online, and use mobile money on our phones. But have we ever stopped to think about *how* the data for these activities travels from our phones or laptops to the rest of the world and back? This lesson will demystify that process. We will explore the "roads" and "highways" that data travels on, which are called transmission media. We will classify them into two main types: Guided (physical cables) and Unguided (wireless signals).
This topic can be broken down into two main parts: the pathways for data (Media) and the equipment that manages the data on those pathways (Devices). Part A: Transmission Media - The Data Highways
A transmission medium is the physical or non-physical path through which data travels from a sender to a receiver. Think of it as the road a car travels on. These roads can be physical (like a tarred road) or non-physical (like the path an aeroplane takes in the sky). Guided Transmission Media (Wired)
Guided media provide a physical path for the signal. The signal is "guided" along a solid medium like a wire or cable. a) Twisted-Pair Cable: Description: This is the most common type of network cable, used in Local Area Networks (LANs). It consists of pairs of insulated copper wires that are twisted together. The twisting helps to reduce electrical interference from other wires and external sources. The blue or grey cables you see connecting computers to the wall sockets in your school's ICT lab are twisted-pair cables. Types: Unshielded Twisted-Pair (UTP) is the most common. Shielded Twisted-Pair (STP) has an extra metal shield for better protection against interference, often used in factories or near heavy machinery. Ghanaian Context: Used extensively in offices, banks (e.g., GCB, Ecobank), universities (e.g., UG, KNUST), and internet cafes across Ghana to connect computers to a network. b) Coaxial Cable: Description: This cable has a single copper conductor at its centre, surrounded by a layer of insulation, then a braided metal shield, and finally an outer plastic cover. It is more resistant to interference than UTP. Ghanaian Context: You are familiar with this! It's the cable used to connect your television to a DSTv or GOtv satellite dish or cable TV service. It carries video and audio signals. c) Fibre-Optic Cable: Description: This is the most advanced and fastest type of guided medium. It transmits data as pulses of light through thin strands of glass or plastic called optical fibres. It is incredibly fast, can carry huge amounts of data over very long distances, and is immune to electrical interference. Ghanaian Context: Major telecommunication companies like MTN, Vodafone, and the government use fibre-optic cables as the "backbone" of the internet in Ghana. These are the undersea cables that land at places like Nungua Beach in Accra, connecting Ghana to the global internet. They also run across the country, linking major cities. Unguided Transmission Media (Wireless)
Unguided media transmit data through the air or space without a physical cable. This is what we call wireless communication. a) Radio Waves: Description: Radio waves are used for communication over short and long distances. They can easily travel through walls and buildings, making them ideal for indoor networking. Ghanaian Context: This is the technology behind your Wi-Fi at home or in a restaurant. It is also used for Bluetooth (connecting your phone to a speaker), and of course, for listening to FM radio stations like Peace FM or Citi FM. b) Microwaves: Description: Microwaves are used for high-speed, long-distance communication. They travel in straight lines and require a clear line-of-sight between the transmitter and receiver. They cannot pass through buildings. Ghanaian Context: Look at the tall communication masts (towers) belonging to MTN, Vodafone, and Telecel. The round, drum-like dishes on them are microwave antennas. They are used to relay signals from one part of the country to another, forming the backbone of the mobile phone network. Satellite communication (like for DSTv) also uses microwaves. c) Infrared: Description: Infrared waves are used for very short-range communication. They cannot penetrate walls and are directional. Ghanaian Context: The most common example is your TV or air conditioner remote control. When you press a button, it sends an infrared signal to the device.