What is transferred via USB on the NFC reader?

Question

NFC

What exactly is it for? Just pass information about the cards? Can she be operated on? Use in your programs, projects?

Answer 1

The most common interfaces for PC to work with smart card readers are interfaces: RS232, PCMCIA and USB. In ancient times, a separate driver was written for each device with its own set of commands for working with the device - which was inconvenient, because. a zoo of readers was bred.
At some point, people thought about the issue of unifying the reader and smart card interfaces, and the PC / SC specification ( www.pcscworkgroup.com/) was developed , which describes the principles of working with smart cards and smart card readers that do not depend on from the equipment manufacturer.
Specifically for USB smart card readers, a unified driver was developed - CCID (chip card interface device).
Answering your question: the USB bus supplies power to the reader + commands for the controller, which can interpret them and / or translate the desired command to the card. Commands for the card can be of a different nature, for example: read/write/authenticate. The instruction set is usually specified in the specification for the microchip in the card.