There was a time when checkouts and cash desks echoed to the sound of shoppers rummaging around in their purses for coins and notes.
Today, you’re more likely to hear the confirmatory beeps of contactless payment processing systems.
From debit cards to smart devices, this transformation in payment processing has been accomplished by something called Near-Field Communication.
The number of Near-Field-compatible devices increases every year, from smartphones to wearable fitness trackers.
So near and yet so far
This technology is underpinned by a radio frequency identification system (RFID) first developed in 1983, but only established as a standard two decades later.
No physical contact is required between a payment device and a checkout terminal as an NFC payment is authorised.
The payment terminal will be anticipating the arrival of an electromagnetic induction device, capable of exchanging information once payment is due.
When a bank card or other NFC-equipped device comes into proximity with the payment platform, data is shared between them.
This is transmitted across very short distances via the 13.56MHz radio frequency band, making it difficult for third-parties to spy on the data (or for other devices to interfere with it).
Data can travel wirelessly over distances of up to four inches, so waving an enabled device towards a contact point should prove sufficient.
Basic information including PIN codes may be transmitted by RFID. The total amount of data rarely exceeds 4Kb, which is sufficient to confirm payment.
(We won’t provide a detailed description of how two loop antennas avoid data conflicts while distributing data via electromagnetic induction, but there’s minimal risk of interference).
Uses for NFC
As highlighted above, contactless payments are the area where NFC is most commonly used at present.
However, it has various other uses – not least in terms of loyalty cards and other account-based data.
Every time you tap an Oyster card against a ticket barrier, an NFC chip deducts journey costs from an outstanding balance, conducting a two-way update between card and barrier.
And speaking of journeys, city centre information boards are increasingly incorporating near-field tags. So are information points in museums and other public buildings like bus shelters.
Passports and identity cards contain similar chips, automating the process of passenger tracking. Indeed, iOS 13 will enable Apple devices to verify passports or other ID documents.
(That might be useful when setting up a new bank account. One tap of a passport would confirm your identity more easily than preparing a selection of photocopied utility bills).
Unlike Bluetooth communications, a power source isn’t necessary. Near-field tags cost a fraction as much as Bluetooth technology to develop, and setup times are vastly reduced.
A single tap might be enough to pair wireless peripherals (such as Bluetooth headsets or a portable speaker) to a primary device such as a smartphone.
Smartphone users may even be able to share files and documents between two handsets, without resorting to third-party platforms such as email or Dropbox.