ACR1255U-J1 – Reference Manual
Version V1.01
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Page 19 of 73
9. The encrypted RND_B[0:15] will be transferred to the data processing server through the
authentication response message.
10. The data processing server will decrypt the message data and compare if the content is equal
to the original RND_B[0:15]. If not, the authentication process will be terminated. Otherwise,
the authentication process is completed and a 16-byte Session Key is created by padding the
first 8 bytes of RND_B to the end of the first 8 bytes of RND_A.
Unidirectional authentication should be used to establish the binding between ACR1255U-J1 and the
paired device. ACR1255U-J1 acts as a peripheral wherein it waits until the device to be paired with
establishes a connection. The device to be paired with will need to send a PIN to complete the
authentication process. By default, the PIN value is 000000.
5.4. Communication Profile
The communication profile should be:
Start byte + Len + Dat Check + Stop byte
Field
Size (bytes)
Description
Start byte
1
Value: 05h
Len
2
Len means the number of bytes in the Datablock field
Datablock
N
Data (the frame format is described in
Section 5.5
Check
1
Check means the XOR values of bytes in Len and Datablock fields
Stop byte
1
Value: 0Ah
5.5. Frame Format
5.5.1.
Data Frame Format
Command
HID Frame
Length (bytes)
Description
CmdMessagType
1
Commands
Length
2
Data length
Slot
1
Default value: 00h
Seq
1
Sequence
Param
1
Parameter
Check
1
Checksum
Data
0-N
Data
The frame format should be:
CmdMessa Slot + Seq + Param + Check + Data
If the total command length, including identifier, length and payload, is greater than 20 bytes, then the
reader or the paired device will automatically divide it into several frames.
