← ACARA Digital Technologies Years 7–8

Ethernet cable

A cable with an RJ45 plug that carries data as electrical signals along twisted pairs of copper wire between a device and a switch or router.

Part of: ACARA Digital Technologies Years 7–8 — Wired and Wireless Networks — Module 13, WA Computer Science ATAR Year 11 — Network Communications — Module 8

Understanding Ethernet cable in ACARA Digital Technologies Years 7–8

What it does: The diagram shows a cable running from a device to a switch, which is the job of an Ethernet cable. Electrical signals in copper weaken over distance, so a typical Ethernet cable is limited to about 100 metres. Ethernet cables hold four twisted pairs of copper wire. Twisting the wires helps reduce interference. The RJ45 plug fits the Ethernet port, which is slightly wider than a phone line port. The headphone jack is much smaller. An Ethernet cable is a wired connection. Radio waves are used by wireless networks such as Wi-Fi.

Common mistakes: An Ethernet cable uses twisted pairs of copper wire, not glass fibre. The line should be wire = "copper twisted pairs". An Ethernet cable links a device to a network device such as a switch or router, not to a keyboard. It should be link_to = "switch".

Class: _____________________  ·  Name: _____________________  ·  Date: _________

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This module's key terms are also in a printable crossword (Modules 54–68) and word search (Modules 13–68).

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Learning
Duo
What kind of signal does an Ethernet cable use to carry data?
Electrical signals along copper wirePulses of light along glass
Matches
Ethernet cable = glass fibres carrying light
↓
Ethernet cables carry electrical signals along copper wires, not light along glass fibres. Light in glass is how fibre optic cable works.
Applying
Meanings
Term
Ethernet cable
Meaning
A cable with an RJ45 plug that carries data as electrical signals along twisted pairs of copper wire between a device and a switch or router.
Practice
cable = Ethernet
Testing
Gaps
An Ethernet cable ends in an plug
Check Answer
Spots
3signal = "electrical"
4wire = "glass fibre"

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Quick Questions

1. What kind of signal does an Ethernet cable use to carry data?
A. Pulses of light along glass
B. Electrical signals along copper wire ✓
Ethernet cables with copper wires carry data as electrical signals. Light pulses are used by fibre optic cables.
2. Which plug is found on the end of an Ethernet cable?
A. RJ45 plug ✓
B. HDMI plug
An RJ45 plug clicks into the Ethernet port on a device, switch or router. HDMI is used for video.
3. What is inside a typical Ethernet cable?
A. Twisted pairs of copper wire ✓
B. A single strand of glass fibre
Ethernet cables hold four twisted pairs of copper wire. Twisting the wires helps reduce interference.
4. An Ethernet cable connects a laptop to which device?
A. A switch or router ✓
B. A Bluetooth speaker only
The cable runs between a device and a switch or router, which lets the device join the network.
5. What is the typical maximum length of one Ethernet cable run?
A. About 10 kilometres
B. About 100 metres ✓
Beyond about 100 metres the electrical signal gets too weak. Longer distances need a switch or fibre optic cable.

Match the Pairs

RJ45 → The plug and port type on the end of an Ethernet cable that connects a device to a switch or router
twisted pair → Two copper wires twisted together inside an Ethernet cable to carry electrical signals
An Ethernet cable plugs into a device and a switch or router to carry data between them → laptop --Ethernet cable--> switch
A typical Ethernet cable run can be at most about 100 metres before the signal gets too weak → max cable length = 100 m
Ethernet cable = glass fibres carrying light → Ethernet cables carry electrical signals along copper wires, not light along glass fibres. Light in glass is how fibre optic cable works.
Ethernet cable = wireless signal from a phone to a router → An Ethernet cable is a wired connection. Data travels along the copper wires inside the cable, not through the air as radio waves.

Key Term

Ethernet cable
A cable with an RJ45 plug that carries data as electrical signals along twisted pairs of copper wire between a device and a switch or router.

Fill in the Blanks

1. An Ethernet cable ends in an RJ45 plug
Hint: Type the name of the plug type that fits into an Ethernet port
2. Ethernet sends data as electrical signals
Hint: Type the kind of signal that travels along copper wire
3. Wires inside are twisted pairs of copper
Hint: Type the metal the twisted wires are made of
4. Typical maximum cable length: 100 metres
Hint: Type the usual maximum length in metres before the signal gets too weak
5. It links a device to a switch or router
Hint: Type the network device that connects wired devices together, besides a router

Spot the Error

Question 1
A cable = "Ethernet"
B plug = "RJ45"
C signal = "electrical"
D wire = "glass fibre"
Line D — An Ethernet cable uses twisted pairs of copper wire, not glass fibre. The line should be wire = "copper twisted pairs".
Question 2
A device = "laptop"
B cable = "Ethernet"
C plug = "RJ45"
D link_to = "keyboard"
Line D — An Ethernet cable links a device to a network device such as a switch or router, not to a keyboard. It should be link_to = "switch".
Question 3
A port = "HDMI"
B cable = "Ethernet"
C wires = "copper"
D pairs = 4
Line A — Ethernet cables end in an RJ45 plug that fits an RJ45 port. HDMI is for video. It should be port = "RJ45".
Question 4
A cable = "Ethernet"
B wire = "copper"
C max_length_m = 1000
D ends = "device and switch"
Line C — A typical Ethernet cable run is at most about 100 metres before the signal weakens too much. It should be max_length_m = 100.
Question 5
A cable = "Ethernet"
B signal = "radio waves"
C carries = "data"
Line B — An Ethernet cable carries data as electrical signals along copper wire. Radio waves are used by wireless networks. It should be signal = "electrical".

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