The plug that does not fit
A new switch arrives with a fibre port. The installer has a cable with a different plug on the end. Nothing fits, and the job stops until the right part comes.
Plugs look alike to a beginner, but each shape has a name and a job. Knowing them stops expensive mistakes.
Key words
| Word | What it means |
|---|---|
| Connector | the plug or socket on the end of a cable |
| Pin | a small metal contact inside a copper connector |
| Ferrule | the small ceramic tube at the tip of a fibre connector |
| Duplex | two fibres in a pair, one to send and one to receive |
| Serial | sending bits one after another along one line |
| Coaxial | a cable with a copper core and a braid screen |
| Latch | a small clip that holds a plug in place |
| Ethernet | the common way to join wired devices in an office |
| Bayonet | a plug that locks with a push and a short twist |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can name six copper and five fibre connectors and say what each is used for.
Starter: copper and fibre
Have a go
Starter: copper and fibre
3 questionsHave a go: your answers are marked here and then forgotten. Sign in if you would like your score kept, and to pick up where you left off.Sign in to keep your score
Your answers are marked here and are not kept. A college account keeps every student’s marks.
Six copper connectors
| Connector | Look | Used for |
|---|---|---|
| RJ-45 | Clear plastic plug, 8 contacts, a clip underneath | Ethernet on twisted pair |
| RJ-11 | Smaller plug, 6 positions, usually 2 or 4 wires used | Phone and broadband lines |
| BNC | Round metal plug that locks with a twist | Coaxial: older CCTV, test kit and old Ethernet |
| DB-9 | D-shaped, 9 pins, two thumbscrews | Serial links such as a console port |
| DB-25 | Wider D-shape, 25 pins | Older serial links and printers |
| F-type | Screw-on round plug with a thin pin | TV, satellite and cable broadband on coaxial |
The cells students fill in are left blank in this preview.
Five fibre connectors
| Connector | Look | Locks by | Notes |
|---|---|---|---|
| LC | Small, square, a clip like a tiny RJ-45 | Push and latch | Very common now. Fits SFP modules |
| SC | Square, bigger than LC | Push and pull snap | Common on panels and older kit |
| ST | Round, metal ring | Bayonet: push and twist | Older multi-mode kit |
| MT-RJ | Small plug holding two fibres | Latch | Older. Rare in new work |
| MPO | Wide rectangular plug | Push and latch | Holds 8, 12 or 24 fibres. Used for very fast links |
The cells students fill in are left blank in this preview.
Check: which connector?
Have a go
Check: which connector?
5 questionsHave a go: your answers are marked here and then forgotten. Sign in if you would like your score kept, and to pick up where you left off.Sign in to keep your score
Your answers are marked here and are not kept. A college account keeps every student’s marks.