2.20417 · Section 2: Input and output devices

Direct data entry and associated devices

Key learnings

Direct data entry — the seven readers
Direct data entry (DDE) is input where a device reads data straight from a source — a card, a printed form, a printed code — instead of a person keying it in, which makes entry faster and removes typing errors. The syllabus names seven devices: magnetic stripe reader, chip and PIN reader, RFID reader, OMR, OCR, bar code reader and QR scanner. Learn each device's own name and precisely what it reads; a vague "it scans things" is never credited.
OMR vs OCR — mark position vs character shape
OMR detects whether a mark is present at a fixed position on a form; it reads no letters or digits at all. Uses: multiple-choice answer sheets, lottery tickets, registers. OCR scans an image of text and recognises the shape of each character, printed or handwritten, turning it into editable digital text. Uses: passport e-gates, digitising books, number plates. The test: does the device care about a mark's POSITION or a character's SHAPE?
Match each reader to a specific real use
Magnetic stripe reader — old payment terminals, hotel key cards, ID cards. Chip and PIN reader — paying by card at a till. RFID reader — contactless payment, toll barriers, stock and livestock tracking, building-entry passes. OMR — multiple-choice sheets, lottery tickets, registers. OCR — passport e-gates, digitising text, number plates. Bar code reader — checkout pricing, stock control, parcel tracking. QR scanner — poster codes, boarding passes.

Common mistakes

Drawn from real examiner reports.

Describing the tag, not the reader

Asked to compare an RFID reader with a bar code reader, candidates describe the tag or printed code instead of the device reading it. "The RFID chip stores data on a tag" describes the tag and scores nothing; "the reader picks up a tag's signal without needing line of sight" describes the device. Writing "bar code" where "bar code reader" was asked fails the same way.

Flagged s23 P12 Q9 · s22 P12 Q5

Chip-and-PIN reader is not the card

The same trap with payment devices: asked about a magnetic stripe reader or a chip and PIN reader, candidates write about the cards. Describe what each READER does — a magnetic stripe reader draws the stripe past a read head by contact, while a chip and PIN reader reads the card's chip and requires a PIN to be typed before it authorises payment.

Flagged w23 P11 Q4

"Reads from a distance" is not a difference

Offered as the difference between an RFID reader and a bar code reader, this earns nothing — both can read at some distance, so it separates neither. State something only one of them does: an RFID reader uses radio waves and needs no line of sight, reading a tag through packaging, whereas a bar code reader needs a clear line of sight to the printed pattern.

Flagged s22 P12 Q5

"More secure" with no because

"A chip and PIN reader is more secure than a magnetic stripe reader" is only half an answer: the comparative is there, the reason is missing. Supply it — chip data is encrypted and the correct PIN must be entered before payment is authorised, whereas a magnetic stripe is unencrypted, can be copied by a hidden skimming device and then reused with no further check.

Flagged w23 P11 Q4

Faster card use ≠ faster transaction

Comparing a chip and PIN reader with a contactless reader, "it is faster to use the card" does not score — it describes handling the card rather than the system. The credited wording is that the transaction is faster, because a contactless reader needs no PIN entered and no card inserted, held and removed. Say what is faster, and say it as a comparison.

Flagged s22 P11 Q5

OMR does not read letters at all

OMR and OCR get confused because both begin by scanning a printed page, and answers that merely echo "OMR reads marks, OCR reads characters" convey no understanding and score nothing. OMR cannot recognise a letter or a digit — it only detects whether a mark sits at a fixed position on the form. Only OCR turns character shapes into editable text.

Flagged s23 P11 Q8

A bar code with a letter is Text

Shown a bar code value such as 4X8219, candidates choose Number/Integer because bar codes have previously been shown as integers. The letter X is not a digit, so a numeric type cannot store it — the data type is Text. Read the characters actually printed in the bar code you are shown rather than assuming every bar code is numeric.

Flagged s23 P11 Q1

Exam tips

Name the exact device
Answer with magnetic stripe reader, chip and PIN reader, RFID reader, OMR, OCR, bar code reader or QR scanner. A bare "scanner" or "reader" is too vague to score, and no credit is given for a brand or trade name.
An advantage needs a comparative
"Advantage", "disadvantage", "compare" and "discuss" all demand a comparison. A benefit alone fails; "more reliable than a magnetic stripe reader" scores. Name the beneficiary too — an advantage to the retailer at a checkout is not the same as an advantage to the customer.
"Explain" needs a because
A bare comparative is not enough on an explain or describe question. Follow it with "because…" and a reason drawn from how the device actually works — how it reads, what it needs from the user, or what it does not require.
Give a specific use, not a vague one
Name a real, concrete use of the named device. For OMR, "multiple choice" is credited but "marking exams" is too vague. Likewise "used in shops" fails where "scanning a product's price at the checkout" scores.

Revision notes