Advanced Card Systems AET63 BioTRUSTKey, Справочное руководство

Страница: 12 / 29

AET63 Reference Manual version 1.8 September 2006
 Advanced Card Systems Ltd. Page 12 of 29
7.2.2 No transmission error with extended response
The response by the AET63 to a correctly received command consists of three protocol bytes, two status
bytes and a variable number of data bytes and has the following structure:
byte 1 2 3 4 5 6 7 ... N+6
(N>0)
N+7
Header SW1 SW2 Data length = N Data Checksum
FF
H
Data Length N
Header 01
H
to indicate the start of the normal response.
02
H
to indicate the start of an encrypted response (support from firmware 0.67 onwards,
only used in PTVerifySC
(*)
and PTVerifySCAll
(*)
)
SW1 Indicates the command execution status:
90
H
= command successfully executed
60
H
= error in command data; command cannot be executed
67
H
= error detected in command execution
FF
H
= status message initiated by the reader
SW2 Further qualification of the command execution status.
A table listing the possible values of the status bytes SW1 and SW2 and the corresponding
meaning is given in Appendix B.
Data Length Number of subsequent data bytes, and is encoded in 3 bytes. The first byte is FF
H
. The
second byte and the third byte represent data length N.
Data Data contents of the command.
For a READ_DATA command, for example, the data bytes would contain the contents of the
memory addresses read from the card. The data bytes can represent values read from the
card and/or status information.
Checksum The checksum is computed by XORing all response bytes including header, status bytes,
data length and all data bytes.
Note (*) : Please refer to “BioTRUSTKey API Manual.doc” for the descriptions of PTVerifySC and
PTVerifySCAll.
7.2.3 Transmission error
If the receiving party of a command (i.e., the AET63) or a response (i.e., the computer) detects an error in
the data length or the checksum of a command, it disregards the received data and sends a "NOT
ACKNOWLEDGE" message to the transmitting party upon completion of the faulty transmission. The "NOT
ACKNOWLEDGE" message consists of two bytes:
byte 1 2
05
H
05
H