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6. NFC operation
Near Field Communication (NFC) is a standard form of communication between an NFC reader and
NFC supported media like smartcards, tags and smart phones.
NFC is a short-range wireless technology, which allows two devices to exchange securely small
amounts of data over a distance of a few centimetres.
The adoption of NFC technology by mobile devices and passports has seen NFC technology gain in
popularity. Consumers can now perform contactless transactions with a single touch, and use NFC
devices for public transport, ticketing and access control.
The LSR118 operates in NFC reader mode and processes NFC (and barcode) data from a single
point of presentation in any orientation.
The NFC module in the LSR118 is Personal Computer/Smart Card
(
PC/SC) compatible and you
can use standard Windows smartcard functions to communicate with the module through the
Windows Smartcard Resource Manager API.
6.1 Summary of operation
An NFC reader reads/writes blocks from/to a microprocessor or MIFARE card. When NFC media
connects to the LSR118’s NFC reader, the device retrieves an Answer to Reset (ATR) from the
card.
The ATR specifies certain communication parameters, including the card’s nature and state.
•
If the ATR identifies a microprocessor card, the host application sends
Application Protocol Data
Unit (
APDU) commands to the card using the Windows Smartcard API.
The format of the command and response APDUs depend on the type of media.
•
If the media type is a MIFARE card, the NFC module constructs an ATR from the fixed elements
that identify the card. See page 33 for more information.
Once the application detects a MIFARE-type card, it can then use MIFARE commands to
communicate with it (see page 39).
The host sends APDU or MIFARE commands to the card over the PC/SC interface using the
SCardTransmit
function in the Windows Smartcard API and gets data back from the card.
Once communication is complete, or a user removes the card, the NFC module disconnects from
the card and waits for another card connection.
Figure 9 shows an overview of the process that the NFC module in the LSR118 uses to identify and
communicate with contactless media.