Choosing a transmission method for a scenario

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A temperature sensor sends readings to a display screen. The sensor never needs to receive anything back. Which direction fits?

A Full-duplex, because data must flow both ways at once

B Simplex, because data only ever flows one way

2. Two engineers use walkie-talkies on a building site. Only one person speaks at a time. Which direction fits?

A Half-duplex, because data goes both ways but not at the same time

B Simplex, because data goes both ways at the same time

3. Two friends talk on a video call and both can speak and be heard at the same time. Which direction fits?

A Full-duplex, because both devices send and receive at the same time

B Half-duplex, because both devices send and receive at the same time

4. Data is sent between two computers in different countries over a long distance. Which bit arrangement is the better choice?

A Serial, because bits sent one after another avoid data skew over long distances

B Parallel, because several bits at once are never affected by distance

5. A printer sits 1 metre from a computer and needs data sent as fast as possible. Which bit arrangement could be justified?

A Serial, because it sends many bits at once, so it is faster over short distances

B Parallel, because the distance is short and sending many bits at once is faster

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Scenario: a computer sends data to a printer 1 m away, and the printer replies only with 'ready' or 'error'. Method: half-duplex, parallel		AMethod: simplex, serial. Because data travels one way only and serial avoids skew over a long distance.
2Scenario: a video call between two offices 500 km apart. Method: full-duplex, serial		BParallel over a long distance suffers data skew, so bits arrive out of sync. Serial should be chosen.
3A TV station broadcasts a programme to many homes. Nothing comes back, and the distance is long.		CBoth sides send and receive at the same time over a long distance, so serial is used to avoid data skew
4Two walkie-talkies on a building site. Only one person speaks at a time over a short distance.		DThe data only goes one way, from the camera to the monitor, so full-duplex is wrong. It should be simplex.
5A security camera streams video to a monitor in the next office. Method: full-duplex, because it sends data both ways.		EMethod: half-duplex, serial. Because data goes both ways but not at the same time.
6Sending a file to a server 3000 km away. Method: parallel, because it sends many bits at once so it is faster.		FTwo-way data, but only one direction at a time, over a very short distance, so parallel is acceptable

Definitions

transmission method

Fill in the Blanks

Complete each line of code by filling in the missing parts.

scenario = "TV remote to TV" direction = _______

scenario = "Walkie-talkie chat" direction = ___________

scenario = "Phone call between two people" direction = ___________

scenario = "500 m between two buildings" bits = ______

scenario = "500 m between two buildings" answer = "Serial _______ the distance is long"

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A Scenario: keyboard to PC

B Direction: simplex

C Bits: serial

D Because: data flows both ways

Question 2

A Scenario: walkie-talkie

B Direction: half-duplex

C Because: two-way, at same time

D Bits: serial

Question 3

A Direction: simplex

B Scenario: video call

C Because: both send at once

Question 4

A Scenario: CCTV to a monitor

B Direction: full-duplex

C Because: video flows one way

Question 5

A Scenario: radio broadcast

B Direction: simplex

C Bits: serial

D Because: listeners can reply

Answer Key

Choosing a transmission method for a scenario

Section A: Quick Questions

B — Simplex, because data only ever flows one way

A — Half-duplex, because data goes both ways but not at the same time

A — Full-duplex, because both devices send and receive at the same time

A — Serial, because bits sent one after another avoid data skew over long distances

B — Parallel, because the distance is short and sending many bits at once is faster

Section B: Match the Pairs

Scenario: a computer sends data to a printer 1 m away, and the printer replies only with 'ready' or 'error'. Method: half-duplex, parallel → Two-way data, but only one direction at a time, over a very short distance, so parallel is acceptable

Scenario: a video call between two offices 500 km apart. Method: full-duplex, serial → Both sides send and receive at the same time over a long distance, so serial is used to avoid data skew

A TV station broadcasts a programme to many homes. Nothing comes back, and the distance is long. → Method: simplex, serial. Because data travels one way only and serial avoids skew over a long distance.

Two walkie-talkies on a building site. Only one person speaks at a time over a short distance. → Method: half-duplex, serial. Because data goes both ways but not at the same time.

A security camera streams video to a monitor in the next office. Method: full-duplex, because it sends data both ways. → The data only goes one way, from the camera to the monitor, so full-duplex is wrong. It should be simplex.

Sending a file to a server 3000 km away. Method: parallel, because it sends many bits at once so it is faster. → Parallel over a long distance suffers data skew, so bits arrive out of sync. Serial should be chosen.

Section C: Definitions

transmission method — Pick the direction (simplex, half-duplex or full-duplex) and the bit arrangement (serial or parallel), then justify both using the scenario's distance, speed and two-way needs.

Section D: Fill in the Blanks

scenario = "TV remote to TV"
direction = simplex

scenario = "Walkie-talkie chat"
direction = half-duplex

scenario = "Phone call between two people"
direction = full-duplex

scenario = "500 m between two buildings"
bits = serial

scenario = "500 m between two buildings"
answer = "Serial because
 the distance is long"

Section E: Spot the Error

D — Simplex means data travels in one direction only, so the reason must say it flows one way. 'Both ways' would need half-duplex or full-duplex. It should read 'Because: data flows one way'.

C — Half-duplex is two-way but only one device sends at a time, so the users take turns. 'At the same time' describes full-duplex. It should read 'Because: two-way, taking turns'.

A — In a video call both people send and receive at the same time, so the direction is full-duplex. Simplex is one-way only. Line 1 should be 'Direction: full-duplex'.

B — The camera only sends video and the monitor only receives it. This one-way need is simplex. Full-duplex is for two-way data at the same time. It should be 'Direction: simplex'.

D — A radio broadcast is simplex because listeners cannot send data back. Saying they can reply contradicts the simplex choice. It should read 'Because: listeners can't reply'.