ACS ACR128, User Manual

Page: 32 / 36

ACR128 Dual Interface Smart Card Reader
7.5.2 Read Value Block
The Read Value Block command is used for retrieving the value from the value block. This
command is only valid for value block.
Table 27-a: Read Value Block APDU Format (5 Bytes)
Command
Class INS P1 P2 Le
Read Value
Block
FF B1 00
Block
Number
00
where,
Block Number : 1 Byte. The value block to be accessed.
Table 27-b: Read Value Block Response Format (4 + 2 Bytes)
Response
Data Out
Result Value
{MSB .. LSB}
SW1 SW2
where,
Value : This is 4 Bytes long. This is the value returned from the card. The value is a signed
long integer (4 bytes).
Example 1: Decimal - 4 = {0xFF, 0xFF, 0xFF, 0xFC}
Value
MSB
LSB
FF FF FF FC
Example 2: Decimal 1 = {0x00, 0x00, 0x00, 0x01}
Value
MSB
LSB
00 00 00 01
Table 27-c: Read Value Block Response Codes
Results SW1 SW2 Meaning
Success 90 00 The operation is completed successfully.
Error 63 00 The operation failed.
Page 32 of 36
ACR128 API
Version 1.7 May 2008