Transmission error, Card status message – ACS AET63 BioTRUSTKey User Manual

Page 11

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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.

6.2.3.

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

If the AET63 responds with a 'NOT ACKNOWLEDGE' message to a command from the computer, the
computer would normally transmit the command again. If the computer detects a transmission error in
a response from the AET63, it can send the 'NOT ACKNOWLEDGE' to the reader upon which the
reader will transmit the most recent response again.

6.3. Card Status Message

When a card is being inserted into the reader or an inserted card is being removed from the reader
while the reader is idle, i.e., not executing a command, the reader transmits a Card Status Message to
notify the host computer of the change in the card insertion status.

In a system where these unsolicited messages from the reader to the computer are not desired, they
can be disabled with the SET_NOTIFICATION command. Please note that the setting made with this
command is volatile and will be lost with the next reader reset or power up. By default, the Card
Status Message will be transmitted by the reader after a reset.

The Card Status Messages have the following structure and contents:

Card Status Message for Card Insertion

Byte

1 2 3 4 5

Header

SW1

SW2

Data

length

Checksum

01

H

FF

H

01

H

00

H

FF

H

Card Status Message for Card Removal

Byte

1 2 3 4 5

Header

SW1

SW2

Data

length

Checksum

01

H

FF

H

02

H

00

H

FC

H

A card status message is transmitted only once for every card insertion or removal event. The reader
does not expect an acknowledge signal from the computer. After transmitting a status message, the
reader waits for the next command from the computer.

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AET63 Reference Manual

Version 2.2

Page 11 of 26

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