May 2006, Issue 190

Mobile Phone Book
M16C/62P-Based Data Backup System
Renesas M16C 2005 Honorable Mention

TPDU PROTOCOL

APDUs are transmitted by the next-level protocol (the transport protocol) defined in the ISO 7816-3 smart card standard. The data structures exchanged by a host and a card using the transport protocol are called transport protocol data units (TPDUs).

The T=0 protocol and the T=1 protocol are the most commonly used transport protocols in smart card systems. The former is byte-oriented, which means that the smallest unit processed and transmitted by the protocol is 1 byte. In contrast, the T=1 protocol is block-oriented. A block, which consists of a sequence of bytes, is the smallest data unit that can be transmitted between a card and a host. The TPDU structures used in the T=0 protocol are different from those used in the T=1 protocol.