Software Development Kit. A set of development utilities meant for writing software applications, usually associated with specific environments.
Low-level software that is similar to hardware features. This software operates by exchanging commands directly with an external device or with a specific software loaded in the product.
This international standard defines the VCD/VICC communication scheme. It is divided into 3 layers:
1. Defines the hardware characteristics of the VICC,
2. Defines the carrier frequency and the bit-level communication scheme,
3. Defines the frame-level communication scheme, the session opening sequence (anti-collision/inventory), and the command set of the VICC.
All VICCs are memory chips. Their data storage area is divided into blocks. The size of the blocks and the number of them depend on the VICC.
Note that ISO 18000-3 mode 1 is the same as ISO 15693
Application protocol datagram unit. These are the frames that are exchanged at application-level between an application running on the computer and a smartcard. The format of those frames is defined by ISO 7816-4 and checked by the system's PC/SC stack. The command (application to card) is called a C-APDU and consists at least of four bytes denoted CLA (class), INS (instruction), P1 and P2 (parameters). The response (card to application) is called a R-APDU and consists at least of two bytes denoted SW1, SW2 (status word). Note that this is a request/response scheme: the smartcard has no way to send something to the application unless the application asks for it.
reader (Microprocessor-based card)
An ICC (or a PICC) whose chip is a small computer. This is the case of high-end cards used in payment, transport, eID/passports, access control... Key features are security, ability to store a large amount of data and to run an application inside the chip. Most of the time they implement the command set defined by ISO 7816-4.
Coupling device or coupler. A device able to communicate with an ICC. This is what everybody calls a smartcard reader. Technically speaking it could be seen as a gateway between the computer and the card.