Input devices get data into a computer; output devices present the results. In the exam, you will often be given a situation – a supermarket, a bank, an exam centre – and asked to choose the most suitable device and justify your choice. This post shows you how.

It builds on Inside the Computer: Input, Processing, Memory, Storage and Output (IPOS).

Build on what you learned in Forms 1–3

These Lower School ICT posts cover the basics of this topic:

• Peripheral Device – devices that connect to the computer, such as printers and scanners
• Keyboards and Keyboard Layout – the most common input device, key by key
• Screen size and resolution – what makes one monitor display better than another

In this post:

• Input devices and where they are used
• Visual output devices (monitors, printers, microfilm)
• Audible output devices
• How to choose a device for a given situation

Input devices

Device	How it works / what it does	Typical application
Keyboard	Keys are pressed to enter text and commands	Typing documents, data entry
Mouse / pointing devices	Moves a pointer on screen; click to select	Using a GUI, graphic design
Optical Mark Reader (OMR)	Detects pencil marks in set positions on a form	Marking multiple-choice answer sheets, lottery tickets
Optical Character Reader (OCR)	Scans printed text and turns it into editable text	Digitising old documents, reading number plates
Magnetic Ink Character Reader (MICR)	Reads characters printed in magnetic ink	Processing cheques in banks
Bar code reader	Reads the pattern of bars on a label	Supermarket checkouts, library books
Document scanner	Captures an image of a page	Scanning certificates and photos
Light pen	Points directly at the screen	Older design and medical systems
Touch screen	User touches the screen to select	Tablets, ATMs, point of sale
Voice response unit / microphone	Captures speech or sound	Phone banking menus, voice notes
Digital camera / webcam	Captures images and video	Online classes, ID photos
Biometric systems	Read fingerprints, face or iris	Clocking in at work, unlocking phones
Sensors	Measure temperature, light, motion, etc.	Weather stations, automatic doors
Remote control / joystick	Send control signals	TVs, gaming

Image source: File:Check with MICR.jpg

Video: OpScan® 16 Scanner – https://www.youtube.com/watch?v=Yd8PWYCT7w8

Video: How Does Optical Character Recognition (OCR) Work? – https://www.youtube.com/watch?v=jO-1rztr4O0

Video: What is Magnetic Ink Character Recognition (MICR) Toner? – https://www.youtube.com/watch?v=LX-FyRcdUmM

Visual output devices

• Monitors – soft copy output on a screen.
• Laser printers – fast, high quality, quiet; good for offices printing many pages.
• Inkjet printers – cheap to buy, good colour photos; slower and ink can be expensive.
• Dot matrix printers – impact printers; noisy, low quality, but can print carbon copies (multi-part forms).
• Thermal printers – use heat on special paper; used for receipts at cash registers and ATMs.
• Plotters – draw large, accurate diagrams such as building plans.
• 3D printers – build solid objects layer by layer; used for prototypes and parts.
• Microfilm – tiny photographic copies of documents for long-term archives.

Image source: File:Microfilm reader UWI.jpg

Image source: File:Microfilm Reels (13434414483).jpg

Video: Printers Explained – Laser, Inkjet, Thermal, & Dot Matrix – https://www.youtube.com/watch?v=JEVurb1uVFA

Image source: File:3D Printing.jpg

Audible output devices

Speakers, headphones and earphones output sound – for music, video lessons, alerts and screen readers for visually impaired users.

How to choose a device in an exam question

• Read the scenario: what data, how much, how fast, and who uses it?
• Pick the device that matches the volume and type of data (e.g. thousands of answer sheets → OMR).
• Justify with a reason linked to the scenario (speed, accuracy, cost, portability, hard copy vs soft copy).

For more videos on each device, see Videos: Input/Output Devices.

Paper 1 practice (multiple choice)

Choose the best answer for each question. Try them all before you check.

1. Which input device is BEST for marking multiple-choice answer sheets?
(A) OCR
(B) OMR
(C) MICR
(D) Light pen

2. Banks use MICR mainly because it
(A) is the cheapest device
(B) reads characters accurately even if they are stamped over
(C) prints receipts
(D) captures fingerprints

3. Which printer can produce carbon copies of a multi-part invoice?
(A) Laser
(B) Inkjet
(C) Dot matrix
(D) Thermal

4. A fingerprint scanner used to clock in at work is an example of a
(A) biometric system
(B) sensor for temperature
(C) plotter
(D) voice response unit

5. Which output device is used to produce a solid plastic model?
(A) Plotter
(B) 3D printer
(C) Microfilm
(D) Thermal printer

Show answers

1. B
2. B
3. C
4. A
5. B

Paper 2 practice (structured question)

A new supermarket in Chaguanas is setting up its checkout counters and office.

(a) Name ONE input device that should be used at each checkout and explain why it is suitable. (2 marks)

(b) Name the type of printer most suitable for printing customer receipts and give ONE reason. (2 marks)

(c) The office manager needs to print 300 high-quality letters a day. Recommend a printer and justify your answer. (2 marks)

(d) State ONE input device that would allow staff to clock in securely, and ONE advantage of using it. (2 marks)

Total: 8 marks

Show answers

(a) Bar code reader (1) – reads product codes quickly and accurately, reducing queue times/typing errors (1). (Accept touch screen/keyboard with valid reason only if linked to checkout.)

(b) Thermal printer (1) – fast, quiet, no ink cartridges needed (1).

(c) Laser printer (1) – fast for high volumes with high-quality output/lower cost per page (1).

(d) Biometric (fingerprint/face) scanner (1) – cannot be lost or shared like a card, so staff cannot clock in for each other (1).

Next: Types of Software: System Software, Application Software and Where Software Comes From

Syllabus link: This post is relevant to the CSEC® Information Technology Syllabus (CXC 30/G/SYLL 17), Section 1: Computer Fundamentals and Information Processing, Specific Objective 6 (“select appropriate input/output devices to meet the needs of specified applications”).

Attributions to media used in this post:

• Check with MICR.jpg – SRI International – CC BY-SA 3.0 (via Wikimedia Commons)
• 3D Printing.jpg – MukhtaromST – CC0 (via Wikimedia Commons)
• Microfilm reader UWI.jpg – Philosopher1234 – CC BY-SA 4.0 (via Wikimedia Commons)
• Microfilm Reels (13434414483).jpg – University of Illinois Library – CC BY 2.0 (via Wikimedia Commons)

Updates

2026/10/16

– Shuffled the answer options in the “Try it: Match the device to the job” activity so they no longer appear in the same order as the questions.
– Added two photos for microfilm output: a microfilm reader and microfilm reels in storage.

© 2026 Vedesh Kungebeharry. All rights reserved.