Which cable is it?
A technician stands in a cupboard with forty cables coming out of a wall. One of them goes to the new manager's desk. It is not labelled.
She could pull each one and ask the manager. That would take all morning. Or she could use a small tool that finds the right cable in a few minutes.
Good technicians test with a plan and the right tools.
Key words
| Word | What it means |
|---|---|
| Test plan | a written list of what to test, how, and what result to expect |
| Tone generator | a tool that puts a signal on a cable so you can find it |
| Probe | a wand that picks up the tone, so you can find the cable that carries it |
| Cable tester | a tool that checks each wire in a cable for faults |
| Tracing kit | the set of tools used to follow and label cable runs |
| Continuity | an unbroken path for a signal along a wire |
| Open | a wire that is broken, so the signal cannot pass |
| Short | two wires that touch when they should not |
| Patch panel | a board of sockets where cables from the walls end |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can write a short test plan and say what a tone generator and probe, a cable tester and a tracing kit are for.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Plan before you test
A test plan says what you will test, how you will test it, what you expect, and who does it. You fill in the real result next to it and mark pass or fail.
Without a plan you forget a test, or you cannot prove you did it. With a plan, anybody can repeat your test and get the same answer.
A tiny test plan
| Test | Tool | Expected result | Actual result | Pass or fail |
|---|---|---|---|---|
| Find the cable for desk 12 | Tone generator and probe | Probe sounds on patch panel port 12 | Port 12 | Pass |
| Check all 8 wires in the cable | Cable tester | Lights 1 to 8 in order | Light 4 missing | Fail |
| Check the cable length | Cable tester with length | Under 90 metres | 47 metres | Pass |
The cells students fill in are left blank in this preview.
Three tools and how to use them
| Tool | What it is | How you use it |
|---|---|---|
| Tone generator and probe | A tone generator sends a tone down a cable. A probe is a wand that picks it up. | Clip the generator on one end. Hold the probe near the cables at the other end or at the patch panel. It beeps loudest at the right one. |
| Cable tester | Two parts, one for each end of a cable | Plug one part in each end. It lights each wire in turn and shows an open, a short or swapped wires. |
| Tracing kit | The set used to follow cable runs | Tone and probe, labels, a torch and a notebook. Use it to follow and label cables through ceilings and floors. |
The cells students fill in are left blank in this preview.
Quick check
Have a go
Quick check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.