Should devices connect by cable or wirelessly, and how?
Compare wired and wireless connectivity, understand how Wi-Fi works, and the role of encryption in wireless networks.
A focused answer to AQA GCSE Computer Science 3.5.2, covering the comparison of wired and wireless connectivity, how Wi-Fi works, and the role of encryption in wireless networks.
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What this dot point is asking
AQA wants you to compare wired and wireless connectivity, explain how Wi-Fi connects devices wirelessly, and explain why encryption is used on wireless networks.
Wired connectivity
The reliability and security come from the signal being contained in the cable: there is no radio interference, no obstruction from walls, and an attacker would need physical access to the cable to intercept it. This is why fixed, performance-critical equipment (servers, desktop machines, games consoles for competitive play) is usually wired.
Wireless connectivity
Wireless lets devices move freely and avoids the cost and disruption of cabling, which is why phones, tablets and laptops rely on it. The trade-offs are that it is usually slower than a wired link, can suffer interference from other devices and obstruction from walls and distance, and the broadcast signal can be intercepted more easily.
Encryption on wireless networks
The exam point is to separate two different jobs. The Wi-Fi password (authentication) controls who is allowed to join the network. Encryption scrambles the actual data in transit. Both are needed, because controlling who joins does not stop someone outside the network from intercepting the radio waves, and only encryption makes those intercepted signals unreadable.
How Wi-Fi connects a device
When a device joins a Wi-Fi network it communicates by radio with a wireless access point, which is often built into a home router. The access point bridges the wireless devices to the wired network and the internet beyond. Several devices can share one access point, taking turns to transmit, which is part of why wireless can slow down as more devices join or as distance and walls weaken the signal. The radio signal spreads out in all directions, which gives wireless its convenience (no cables, free movement) but also its main weakness, because any device in range can pick up the signal, which is the reason encryption is essential.
Try this
Q1. Give one advantage and one disadvantage of a wireless connection compared with wired. [2 marks]
- Cue. Advantage: devices can move freely with no cables. Disadvantage: usually slower and easier to intercept.
Q2. State why wireless networks use encryption. [1 mark]
- Cue. So that intercepted data cannot be read without the key, keeping it private.
Exam-style practice questions
Practice questions written in the style of AQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AQA 20184 marksCompare wired and wireless connections. Give two ways a wired connection is better and one situation where a wireless connection is the better choice.Show worked answer →
A wired connection is generally faster, because cables (especially fibre) carry more data with less delay; it is also more reliable, because it is not affected by radio interference or obstructions, and more secure, because the signal is contained in the cable rather than broadcast.
A wireless connection is the better choice where devices need to move freely or where running cables is impractical, for example phones and laptops around a building, or a cafe where customers connect their own devices.
Markers reward two valid advantages of wired (from faster, more reliable, more secure) and a sensible situation favouring wireless (mobility or impractical cabling).
AQA 20213 marksExplain why a wireless network uses encryption, and explain why a password alone is not enough to keep the data private.Show worked answer →
A wireless network broadcasts data as radio waves that spread out and can be intercepted by any device in range, so encryption is used to scramble the data with a key, meaning an intercepted signal cannot be read without the key.
A password alone controls who is allowed to join the network, but it does not scramble the data being sent; without encryption, data in transit could still be read by someone intercepting the radio signal. Authentication and encryption do different jobs, so both are needed.
Markers reward the interception point (radio waves can be picked up), encryption scrambling the data, and the distinction that a password controls access whereas encryption protects the data itself.
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Sources & how we know this
- AQA GCSE Computer Science (8525) specification — AQA (2020)