Wired and wireless connections trade off against each other. Wired links usually give stable speed and stronger security but need cables and fixed positions. Wireless links give movement and easy setup but depend on range, obstacles and signal quality.
This lesson is part of the networks and communication module and follows the router’s role, since devices reach the router by cable or by radio signal.
What are the constraints?
| Constraint | Wired | Wireless |
|---|---|---|
| Speed and stability | Steady, little interference | Varies with distance, walls and other devices |
| Mobility | Device stays near a socket | Device can move around |
| Installation | Cables to run and sockets to place | Fewer cables, quick to add devices |
| Security | Needs physical access | Signal can be received in range, so encryption matters |
| Cost | Cable and fitting cost | Access point cost, cheaper to extend |
How do I choose, step by step?
- List the activities (video calls, large file transfers, browsing).
- Mark which devices move and which stay in one place.
- Check the building for distance, thick walls and many users.
- Match each constraint to the need, then decide: wired for fixed heavy users, wireless for movers, or a mix.
Worked example
A fictional design studio has 8 desktop computers that send large files, plus visitors who bring phones and laptops. It needs to move a 600 MB project file between two fixed computers.
Choice: wire the 8 desktops to a switch for steady speed and security, and offer wireless to visitors for movement. The mix matches each need.
Transfer time on a wired link rated at 100 Mbit/s:
- Convert the file to megabits: 600 MB × 8 = 4800 Mbit.
- Divide by the speed: 4800 ÷ 100 = 48 seconds, if the link runs at full rated speed.
If the effective speed is only 40 Mbit/s: 4800 ÷ 40 = 120 seconds, which is 2 minutes.
The difference shows why real, steady speed matters more than the rated figure.
The mistake to watch for
A common slip is to divide the file size in megabytes straight by the speed in megabits.
Mistaken answer: 600 ÷ 100 = 6 seconds
This mixes megabytes with megabits, so the answer is 8 times too small.
The correction is to multiply megabytes by 8 first. Another slip is to claim wireless is “always slower” or wired is “always safer”. Say what the constraint is and tie it to the scenario.
Check yourself
1. How long does a 250 MB file take on a steady 50 Mbit/s link?
Show answer
250 × 8 = 2000 Mbit. 2000 ÷ 50 = 40 seconds.
2. A 90 MB file is sent at an effective 30 Mbit/s. How long does it take?
Show answer
90 × 8 = 720 Mbit. 720 ÷ 30 = 24 seconds.
3. A fictional library wants study tablets that students carry between shelves. Wired or wireless, and give one constraint.
Show answer
Wireless. The tablets move, so cables would limit use. Wireless suits mobility, though the library should use encryption because the signal travels through the air.
Where this leads next
Move on to distinguishing intranet and internet access, then use the practice set for mixed calculations and explanations. The mistake log and retest queue is useful for tracking any unit slips.
Calculation slips such as megabits versus megabytes cost easy marks. A teacher in online one-to-one ICT tuition can build a short habit of checking units with you.