The cable that was too long
A school buys the cheapest cable for a run across a playground, 150 metres, from one building to the next. The link drops out every few minutes.
The cable was fine. It was the wrong kind for that distance. Choosing the right medium for each link is half of a good build.
By the end of this lesson
Note
I can choose the right connection, device and access for each group of users.
Key words
| Word | What it means |
|---|---|
| Medium | what carries the signal, such as copper cable, fibre or radio |
| Copper cable | a cable with copper wires that carries electrical signals |
| Fibre | a thin glass cable that carries light, good for long distances |
| Access point | a device that gives Wi-Fi to nearby devices |
| End user device | the device a person uses, such as a laptop or a phone |
| Availability | how much of the time a system works when people need it |
| Back-end system | a server or service that users do not see, such as one that stores records |
The cells students fill in are left blank in this preview.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
This is practice
Important
You cannot run a cable or measure Wi-Fi in a browser, so this lesson is about choosing and giving reasons. Cable work is done on site with a qualified person. The real task has its own tools and brief. Ask your teacher what it lets you configure.
Worked example: which medium for which link?
| Medium | Good for | Watch out for |
|---|---|---|
| Copper cable (twisted pair) | Desks, printers and servers up to 100 metres from the switch | Longer runs lose the signal. It can pick up electrical noise |
| Fibre | Long runs, between buildings, and the busiest links | Costs more and needs special tools to join |
| Wi-Fi | Laptops, phones, visitors and places where cable is hard | Slower when busy, and open to listening unless it is secured |
| Mobile data (4G or 5G) | A back-up link out, or a site with no line | Costs per amount of data, and the signal varies |
The cells students fill in are left blank in this preview.
Set up wireless with care
Wi-Fi is easy to join and easy to listen to. Set it up with three habits.
Use the strongest security the devices support, such as WPA3, or WPA2 if some devices are older. Give visitors their own Wi-Fi, apart from the office. Put access points where people are, and keep the signal inside the building as far as you can.