Wi-Fi and Wired Connections

Devices can connect to a network using either wired connections (typically Ethernet cables) or wireless connections (typically Wi-Fi). Each method has its own advantages and disadvantages. This lesson covers both types and helps you understand when each is most appropriate.

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Wired Connections (Ethernet)

A wired connection uses physical cables to connect a device to the network. The most common type is an Ethernet connection using copper twisted-pair cables (e.g. Cat5e or Cat6) or fibre optic cables.

How Ethernet Works

1. The device's NIC is connected to a switch or router via an Ethernet cable.
2. Data is transmitted as electrical signals through copper cables, or as light pulses through fibre optic cables.
3. The cable provides a direct, physical link between the device and the network.

Types of Ethernet Cable

Cable Type	Maximum Speed	Maximum Length	Notes
Cat5e	1 Gbps	100 metres	Common in homes and offices
Cat6	10 Gbps (short distances)	55 metres (at 10 Gbps)	Better shielding, less interference
Cat6a	10 Gbps	100 metres	Improved version of Cat6
Fibre optic	100+ Gbps	Several kilometres	Uses light; immune to interference

Advantages of Wired Connections

• Speed — generally faster and more consistent than wireless. Gigabit Ethernet is standard.
• Reliability — not affected by interference from other devices, walls or distance (within cable limits).
• Security — more difficult to intercept; an attacker would need physical access to the cable.
• Latency — lower latency (delay) than wireless, making wired connections better for gaming and real-time applications.
• Stability — the connection does not drop out or fluctuate like Wi-Fi can.

Disadvantages of Wired Connections

• Mobility — devices are tethered to a cable and cannot move freely.
• Installation — cables need to be routed through walls, floors or cable trays, which can be costly and disruptive.
• Clutter — cables can be unsightly and create trip hazards.
• Scalability — adding new devices requires additional cabling and switch ports.
• Inconvenience — not practical for mobile devices like phones and tablets.

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Wireless Connections (Wi-Fi)

Wi-Fi uses radio waves to transmit data between devices and a Wireless Access Point (WAP). Wi-Fi follows the IEEE 802.11 family of standards.

How Wi-Fi Works

1. A WAP (or wireless router) broadcasts a radio signal within a certain range.
2. Devices with wireless NICs detect the signal and connect by providing the correct SSID (network name) and password.
3. Data is transmitted as radio waves between the device and the WAP.
4. The WAP forwards the data onto the wired network.

Wi-Fi Standards

Standard	Also Known As	Maximum Speed	Frequency
802.11n	Wi-Fi 4	600 Mbps	2.4 GHz and 5 GHz
802.11ac	Wi-Fi 5	3.5 Gbps	5 GHz
802.11ax	Wi-Fi 6	9.6 Gbps	2.4 GHz and 5 GHz

Frequency Bands

Wi-Fi operates on two main frequency bands:

Band	Range	Speed	Interference
2.4 GHz	Longer range, better at passing through walls	Slower maximum speed	More prone to interference (microwaves, Bluetooth, other Wi-Fi networks)
5 GHz	Shorter range	Faster maximum speed	Less interference but weaker through walls

Advantages of Wireless Connections

• Mobility — users can move freely around the coverage area while staying connected.
• Convenience — no cables needed; easy to connect phones, tablets, laptops and IoT devices.
• Easy to set up — no need to run cables through walls.
• Scalability — additional devices can connect without extra cabling.
• Essential for mobile devices — phones and tablets rely on wireless connectivity.

Disadvantages of Wireless Connections

• Speed — generally slower than wired connections, especially at distance.
• Interference — radio signals can be disrupted by walls, other electronic devices and competing Wi-Fi networks.
• Security — radio signals can be intercepted by anyone within range. Encryption (WPA2/WPA3) is essential.
• Range — signal weakens with distance and through obstacles.
• Latency — higher latency than wired connections.
• Shared bandwidth — many devices sharing the same WAP can cause congestion.

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Wired vs Wireless: Comparison

Feature	Wired (Ethernet)	Wireless (Wi-Fi)
Speed	Faster (1-10 Gbps typical)	Slower (variable)
Reliability	Very reliable	Can drop out
Security	More secure	Requires encryption
Mobility	Fixed location	Move freely
Installation	Cables required	No cables
Latency	Low	Higher
Cost	Cable and installation costs	WAP cost; less cabling
Best for	Desktops, servers, gaming	Phones, tablets, laptops

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Bluetooth

Bluetooth is a short-range wireless technology used to create PANs (Personal Area Networks).

Key facts about Bluetooth

• Range — typically up to 10 metres (some versions up to 100 metres).
• Speed — slower than Wi-Fi (typically 1-3 Mbps).
• Uses — connecting headphones, keyboards, mice, speakers, smartwatches and file sharing between nearby devices.
• Power — uses less power than Wi-Fi, making it suitable for battery-powered devices.
• Pairing — devices must be "paired" to establish a connection.

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Choosing the Right Connection

Scenario	Best Connection	Reason
Desktop computer in an office	Wired (Ethernet)	Fastest, most reliable
Smartphone browsing at home	Wireless (Wi-Fi)	Mobility required
Online gaming	Wired (Ethernet)	Lowest latency
Connecting headphones to a phone	Bluetooth	Short range, low power
Laptop in a coffee shop	Wireless (Wi-Fi)	Mobility and convenience
Server in a data centre	Wired (Fibre optic)	Maximum speed and reliability

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Summary

• Wired connections use Ethernet cables and offer faster, more reliable and more secure connectivity.
• Wireless connections (Wi-Fi) use radio waves and offer mobility and convenience.
• Bluetooth is a short-range wireless technology for personal devices.
• The choice between wired and wireless depends on the needs of the user: speed, mobility, security and cost.

Exam Tip: You may be asked to recommend wired or wireless for a given scenario. Always justify your answer with specific advantages relevant to that scenario.

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Deeper dive: WiFi frequencies, channels and worked range examples