Wired and wireless connectivity
Networks transmit data over physical media. The big choice is wired (copper, fibre) vs wireless (Wi-Fi, Bluetooth). Each has trade-offs in speed, range, cost and reliability that AQA expects you to compare.
Wired connectivity
Copper cable (twisted pair / Ethernet)
- Most common LAN cable: Cat 5e/6/6a Ethernet.
- Speed: 1 Gbps (Cat 5e) up to 10 Gbps (Cat 6a).
- Range: up to ~100 m per segment.
- Cost: cheap.
- Reliable, immune to most environmental noise.
Fibre-optic cable
- Glass or plastic strands carrying pulses of light.
- Speed: 10 Gbps to 100 Gbps+ — extremely high.
- Range: kilometres without amplification.
- Cost: more expensive cable and connectors than copper.
- Immune to electromagnetic interference.
- Used for backbones, ISP infrastructure, data centres, between buildings.
Wired pros
- Higher speed than wireless (especially fibre).
- Stable, low latency, predictable.
- Harder to eavesdrop without physical access.
- Less affected by interference.
Wired cons
- Physical cabling requires installation and walls drilled.
- Restricts mobility — devices must stay near a port.
- Expensive to run cables to many endpoints.
Wireless connectivity
Wi-Fi
- Radio waves at 2.4 GHz or 5 GHz (and 6 GHz in Wi-Fi 6E).
- Speed: depends on standard. Wi-Fi 5: ~1 Gbps; Wi-Fi 6: ~3 Gbps.
- Range: indoor ~30-50 m, outdoor further.
- Convenient — connect any device with a Wi-Fi adapter.
Bluetooth
- Short-range radio (typically <10 m).
- Speed: low (1-3 Mbps).
- Used for personal-area networking — wireless mice, headphones, file transfer between phones.
- Lower power than Wi-Fi.
Wireless pros
- No cables — mobility, easy installation in existing buildings.
- Quick to add new devices.
- Cheap for small networks (one router).
Wireless cons
- Slower than wired (especially fibre).
- Range limited; signals weaken through walls.
- Interference from other devices and networks.
- Less secure — radio signals leak; needs strong encryption (WPA2/WPA3).
Comparison summary
| Feature | Copper Ethernet | Fibre | Wi-Fi | Bluetooth |
|---|---|---|---|---|
| Max speed | 10 Gbps | 100+ Gbps | ~3 Gbps | ~3 Mbps |
| Range | ~100 m | Kilometres | ~30-50 m | ~10 m |
| Cost | Low | High | Moderate | Low |
| Mobility | None | None | Yes | Yes |
| Reliability | High | Very high | Moderate | Moderate |
| EM interference | Some | None | Strong | Some |
Choosing for a use case
- Connecting a server to a backbone: fibre — speed and reliability matter.
- Office desktop: wired Ethernet — fast, stable, cheap.
- Visitor laptops: Wi-Fi — must be mobile.
- Phone to wireless headphones: Bluetooth — short-range, low-power.
- Building-to-building link: fibre — long range, no interference.
- Smart-home temperature sensor: Wi-Fi or Bluetooth depending on hub.
✦Worked example
A small office wants reliable, fast networking for 8 desktops and convenient Wi-Fi for visitors. Recommend a setup.
- Wired Ethernet to each desktop — fast, low cost, stable B1B1.
- Wi-Fi access point for visitor laptops and phones — mobility B1.
- Both connect to the same router; Wi-Fi can be on a guest network B1.
⚠Common mistakes— Pitfalls
- Saying "fibre is wireless" — it's wired (light through glass).
- Treating Wi-Fi and Bluetooth as the same. Different range, speed and use cases.
- Assuming wireless is always slower. Wi-Fi 6 vs older copper Ethernet — wireless can win.
- Ignoring interference. Microwaves, neighbours' Wi-Fi, walls all degrade signals.
- Forgetting EMI advantage of fibre. In factories or hospitals, fibre is preferred for noise immunity.
➜Try this— Quick check
For each, choose wired or wireless:
- Connecting a smartwatch to a phone: wireless (Bluetooth).
- A high-frequency-trading server: wired (fibre).
- A coffee-shop customer's laptop: wireless (Wi-Fi).
- A factory's CNC machine network: wired (often fibre for EMI).
AI-generated · claude-opus-4-7 · v3-deep-computer-science