ITPEC IP October 2022 Question 12

Communication over about 10 cm, used to read and write IC cards and IC tags — NFC (Near Field Communication) is a very short-range radio standard.

NFC uses the 13.56 MHz band and works only when two devices are held within about 10 cm of each other, usually by touching them together. The same technology is in contactless IC cards and tags, so an NFC reader or smartphone can read and write them: transport tickets, electronic money, building passes and smartphone payments. The short range is deliberate: a card is read only when its holder brings it to the reader.

Answer (a)

Why not others:

• •(b) — radio over tens of meters for a wireless LAN is Wi-Fi (IEEE 802.11)
• •(c) — infrared data exchange between mobile phones is IrDA, which uses light, not radio
• •(d) — positioning from the signals of several satellites is GPS (GNSS), used in car navigation

Key rule: Short-range wireless links by range: NFC about 10 cm (touch), IrDA about 1 m (infrared, line of sight), Bluetooth about 10 m, wireless LAN tens of meters.

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