Connectivity: Edexcel IGCSE Information and Communication Technology Complete Notes

Connectivity is Topic 2 in the Edexcel IGCSE (4IT1) Information and Communication Technology specification. It covers how digital devices communicate, the networks they use, and how data is protected across those networks. This is examined on Paper 1.

Straight to it. The connectivity edexcel igcse content breaks into five areas: types of digital communications, factors that influence communication choice, requirements for connecting to a network (including the internet), benefits of using a LAN or home network, and securing data on a network. Each one carries its own set of definitions, comparisons and applied scenarios that the exam can test. These edexcel igcse information and communication technology revision notes walk through every area in the order the specification presents them.

Types of digital communications

Digital devices communicate in four broad ways:

Satellite - signals are sent to an orbiting satellite and relayed back to a different ground location. Used for GPS, satellite TV and communication in remote areas where ground infrastructure does not exist.
Broadcast (TV, radio) - a one-to-many transmission from a central transmitter to receivers. Digital TV and digital radio are broadcast communications.
Wired (cable) - data travels through physical cables such as copper Ethernet cables or fibre-optic cables. Reliable and fast, but the device must be physically connected.
Wireless - data travels through radio waves or infrared signals without physical cables. Flexible and mobile, but potentially slower and less secure than wired connections.

Devices can communicate device to device (Bluetooth file transfer between two phones) or through networks:

Network type	What it is	Example
LAN (Local Area Network)	A network covering a small geographical area such as a building or campus	A school network connecting all the computers in the ICT suite
WAN (Wide Area Network)	A network covering a large geographical area, often connecting multiple LANs	The internet is the largest WAN
PAN (Personal Area Network)	A very small network centred on one person, typically within a few metres	A smartphone connected to wireless earbuds and a smartwatch via Bluetooth
Tethering	Sharing a mobile device's internet connection with another device	Using a smartphone as a Wi-Fi hotspot for a laptop

Types of wireless communication

Technology	Range	Typical use
Wi-Fi	Up to about 100 metres indoors	Connecting devices to a local network and the internet wirelessly
Bluetooth	Up to about 10 metres	Short-range device-to-device connections (headphones, file transfer)
GPS (Global Positioning System)	Global (satellite-based)	Navigation and location tracking
3G / 4G	Cellular coverage area	Mobile internet access and data transfer
Infrared (IR)	Very short range, line of sight required	Remote controls, some older device-to-device transfers
NFC (Near Field Communication)	A few centimetres	Contactless payment, quick device pairing

Wi-Fi vs Bluetooth - know the difference. Wi-Fi connects devices to a network (and typically the internet) over a range of up to about 100 metres. Bluetooth connects devices directly to each other over a short range (about 10 metres). Wi-Fi uses more power but offers faster data transfer. Bluetooth uses less power and is ideal for peripherals like headphones and keyboards. This comparison is tested regularly on Paper 1.

Factors influencing the choice of digital communication

The igcse 4it1 connectivity specification requires you to understand what affects how well a network connection works.

Speed and volume of data transfer depend on the type of connection (wired is generally faster than wireless), the quality of the cable or signal, the distance between devices, and the number of users sharing the connection.

Wired vs wireless in local networks:

Factor	Wired	Wireless
Speed	Generally faster and more consistent	Can be slower, varies with signal strength
Reliability	Very reliable; not affected by interference	Subject to interference from walls, other devices, distance
Mobility	Devices must stay connected to the cable	Users can move freely within range
Installation	Requires running cables through walls and floors	Easier and cheaper to set up
Security	More secure; requires physical access to the cable	Less inherently secure; signals can be intercepted

Bandwidth is the maximum amount of data that can be transmitted over a connection in a given time period. Higher bandwidth means more data can flow, which means faster downloads and smoother streaming. Latency is the delay between sending a request and receiving a response. Low latency is critical for real-time applications such as video calls and online gaming. A connection can have high bandwidth but also high latency, which would allow large file downloads but make video calls laggy.

Broadband, mobile broadband and cellular networks: Broadband is a high-speed internet connection delivered through a telephone line (DSL), cable or fibre optic. Mobile broadband uses the cellular network (3G/4G) to provide internet access to mobile devices. Cellular networks are the infrastructure of base stations and towers that provide mobile phone and mobile broadband coverage.

Requirements for connecting to a network, including the internet

The edexcel igcse information and communication technology connectivity content requires you to know the components needed to connect to a network.

Network operating systems manage network functions such as user access, file sharing and security. Devices on a network are identified by:

Device name - a human-readable label assigned to the device (e.g., "Reception-PC")
IP address (Internet Protocol) - a numerical address that identifies the device on the network (e.g., 192.168.1.5). IP addresses can be assigned dynamically (changing each time the device connects) or statically (fixed).
MAC address (Media Access Control) - a unique hardware address burned into the device's network adapter at manufacture. Unlike an IP address, a MAC address does not change.

Components of wired and wireless systems:

Cable - the physical medium (Ethernet, fibre optic) connecting devices in a wired network
Wireless access point (WAP) - a device that allows wireless devices to connect to a wired network
Router - directs data packets between networks, choosing the best path for each packet
Gateway - connects two different types of network or protocols, translating between them
Booster / repeater - extends the range of a wireless signal by receiving and retransmitting it
Server - a powerful computer that provides services (files, email, web pages, applications) to other devices on the network

Connecting to and using the internet: A web browser is the software used to view web pages. An ISP (Internet Service Provider) provides the actual internet connection. A search engine helps users find information on the internet. Filter software blocks access to inappropriate or harmful content.

Benefits of using a LAN / home network

The specification requires you to know the difference between two network models:

Peer-to-peer network: All computers are equal. Each device can share files and resources directly with other devices. There is no central server. Suitable for small networks (home, small office). Easy to set up but harder to manage as the network grows.

Client-server network: A central server manages the network. Client devices request services from the server. The server controls user access, stores files centrally and manages backups. More complex to set up but easier to manage at scale.

Benefits of using a LAN:

Shared peripherals (one printer can serve an entire office, reducing cost)
Shared data (files stored centrally can be accessed by authorised users from any workstation)
Flexible access (users can log in from different workstations)
Media streaming (music, video and other media can be shared across the network)
Communication (internal messaging, email and scheduling across the network)
Shared internet access (one internet connection can serve all devices on the LAN)

Additional benefits of a client-server network:

Control of user access rights (the server determines who can access what)
Centralised administration (one point of management for the entire network)
Centralised backup (data is backed up from the server, not from each individual machine)
Shared software (applications installed on the server can be accessed by clients)
Shared storage and file access (files stored on the server are accessible to authorised users)
Roaming profiles / hotdesking (a user can log in to any workstation and access their own desktop, files and settings)

Securing data on a network, including the internet

The final part of the connectivity topic covers how data is protected on networks. This area is heavily examined because it connects directly to real-world security concerns.

Security method	What it does
Log-ins and passwords	Verify the identity of users before granting access to the network or a system
Firewalls	Monitor incoming and outgoing network traffic and block unauthorised access based on security rules
WEP / WPA	Wireless security protocols that encrypt data transmitted over a Wi-Fi network. WPA is more secure than WEP.
Encryption	Converts data into an unreadable format that can only be decoded with the correct key
VPN (Virtual Private Network)	Creates an encrypted tunnel between a device and a network, protecting data from interception on public networks
File access rights	Control which users can read, write, modify or delete specific files and folders
Transaction logs	Record all activities and changes made on the network, providing an audit trail for investigation
Backups	Copies of data stored separately so that data can be restored if the original is lost, corrupted or deleted

Selecting security methods for context. The exam often gives a scenario and asks which security methods are appropriate. A home Wi-Fi network needs WPA encryption and a strong password. A business with remote workers needs a VPN. A school network needs file access rights (students should not access staff files) and a firewall. Match the method to the threat in the scenario, and you will earn full marks.

Common mistakes

Confusing LAN, WAN and PAN. A LAN covers a building or campus. A WAN covers a large area (city, country, the world). A PAN covers a person's immediate space. Size is the distinguishing factor.
Stating that Wi-Fi is the internet. Wi-Fi is a way of connecting wirelessly to a local network. The internet is a global WAN. Wi-Fi provides access to the internet through a router, but it is not the internet itself.
Confusing encryption and a firewall. Encryption scrambles data so it cannot be read without a key. A firewall blocks unauthorised traffic. They do different jobs and are not interchangeable.
Mixing up IP address and MAC address. An IP address is assigned by the network and can change. A MAC address is built into the hardware and is permanent. Both identify a device, but in different ways.

Self-check questions

State two differences between Wi-Fi and Bluetooth.
A company has offices in London and New York. State what type of network would connect the two offices, and explain why.
Describe the function of a router in a network.
Explain the difference between bandwidth and latency.
A small business is setting up a network for five computers. State whether a peer-to-peer or client-server network would be more suitable, giving two reasons for your answer.
A school wants to prevent students from accessing inappropriate websites. Identify one security measure the school should use and explain how it works.

These edexcel igcse information and communication technology practice questions test the kind of applied reasoning Paper 1 demands. The edexcel igcse information and communication technology notes in this section cover every area the specification lists, but the exam will test your ability to apply this knowledge to scenarios you have not seen before. Practise by reading a scenario, identifying the relevant connectivity concepts, and writing a clear, direct answer that names specific technologies and explains why they are suitable. That is how marks are earned in the edexcel igcse information and communication technology explained style the examiners look for.