ACS ACR1255U-J1 User manual

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Reference Manual V1.01
ACR1255U-J1
Bluetooth®
NFCReader

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Table of Contents
1.0. Introduction .............................................................................................................5
1.1. Symbols and Abbreviations...................................................................................................5
2.0. Features ...................................................................................................................6
3.0. System Block Diagram............................................................................................7
4.0. Hardware Design...................................................................................................10
4.1. Battery..................................................................................................................................10
4.1.1. Battery charging..........................................................................................................10
4.1.2. Battery life ...................................................................................................................10
4.2. Bluetooth Interface...............................................................................................................10
4.3. USB Interface ......................................................................................................................10
4.3.1. Communication Parameters .......................................................................................10
4.3.2. Endpoints ....................................................................................................................11
4.4. NFC Interface ......................................................................................................................11
4.4.1. Carrier Frequency.......................................................................................................11
4.4.2. Card Polling.................................................................................................................11
4.5. User Interface ......................................................................................................................11
4.5.1. Keys ............................................................................................................................11
4.5.2. Mode Selection Switch................................................................................................12
4.5.3. Status LED..................................................................................................................13
4.5.4. Buzzer.........................................................................................................................14
5.0. Software Design ....................................................................................................15
5.1. Bluetooth Connection Flow..................................................................................................15
5.2. Profile Selection...................................................................................................................16
5.3. Authentication......................................................................................................................17
5.4. Communication Profile.........................................................................................................19
5.5. Frame Format......................................................................................................................19
5.5.1. Data Frame Format.....................................................................................................19
5.6. Bluetooth Communication Protocol .....................................................................................20
5.6.1. Card Power On ...........................................................................................................21
5.6.2. Card Power Off ...........................................................................................................22
5.6.3. Get Slot Status............................................................................................................23
5.6.4. APDU Command.........................................................................................................24
5.6.5. Notify Card Status Command.....................................................................................25
5.6.6. Hardware Error Response ..........................................................................................26
5.6.7. Escape Command.......................................................................................................27
5.7. Mutual Authentication and Encryption Protocol...................................................................29
5.7.1. Bluetooth Authentication Program Flow......................................................................29
5.7.2. SPH_to_RDR_ReqAuth..............................................................................................29
5.7.3. RDR_to_SPH_AuthRsp1............................................................................................30
5.7.4. SPH_to_RDR_AuthRsp..............................................................................................31
5.7.5. RDR_to_SPH_AuthRsp2............................................................................................32
5.7.6. RDR_to_SPH_ACK (Error handling) ..........................................................................33
6.0. Host Programming (PC-linked) API......................................................................34
6.1. PC/SC API...........................................................................................................................34
6.1.1. SCardEstablishContext...............................................................................................34
6.1.2. SCardListReaders.......................................................................................................34
6.1.3. SCardConnect.............................................................................................................34
6.1.4. SCardControl ..............................................................................................................34
6.1.5. ScardTransmit.............................................................................................................34
6.1.6. ScardDisconnect.........................................................................................................34
6.1.7. APDU Flow..................................................................................................................35
6.1.8. Escape Command Flow..............................................................................................36
6.2. Contactless Smart Card Protocol ........................................................................................37

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6.2.1. ATR Generation..........................................................................................................37
6.3. Pseudo APDU for Contactless Interface .............................................................................40
6.3.1. Get Data......................................................................................................................40
6.4. PICC Commands for MIFARE® Classic (1K/4K) memory cards ........................................41
6.4.1. Load Authentication Keys ...........................................................................................41
6.4.2. Authentication for MIFARE® Classic (1K/4K).............................................................42
6.4.3. Read Binary Blocks.....................................................................................................45
6.4.4. Update Binary Blocks..................................................................................................46
6.4.5. Value Block Operation (INC, DEC, STORE) ..............................................................47
6.4.6. Read Value Block........................................................................................................48
6.4.7. Copy Value Block........................................................................................................49
6.5. Accessing PC/SC-compliant tags (ISO 14443-4)................................................................50
6.6. Peripherals Control..............................................................................................................52
6.6.1. Get Firmware Version.................................................................................................53
6.6.2. Get Serial Number ......................................................................................................54
6.6.3. LED Control (in USB Mode only)................................................................................55
6.6.4. LED Status..................................................................................................................56
6.6.5. Buzzer Control ............................................................................................................57
6.6.6. Set LED and Buzzer Status Indicator Behavior..........................................................58
6.6.7. Read LED and Buzzer Status Indicator Behavior.......................................................59
6.6.8. Set Automatic PICC Polling ........................................................................................60
6.6.9. Read Automatic PICC Polling.....................................................................................62
6.6.10. Set PICC Operating Parameter ..................................................................................63
6.6.11. Read PICC Operating Parameter...............................................................................64
6.6.12. Set Auto PPS..............................................................................................................65
6.6.13. Read Auto PPS...........................................................................................................66
6.6.14. Antenna Field Control .................................................................................................67
6.6.15. Read Antenna Field Status.........................................................................................68
6.6.16. Card Emulation Mode Conversion..............................................................................69
6.6.17. Sleep Mode Option .....................................................................................................70
6.6.18. Change Tx Power command ......................................................................................71
6.6.19. Read Tx Power Value.................................................................................................72
List of Figures
Figure 1 : ACR1255U-J1 Architecture....................................................................................................7
Figure 2 : ACR1255U-J1 USB Communication Architecture.................................................................8
Figure 3 : BluetoothSmart Protocol Stack .............................................................................................9
Figure 4 : Keys on ACR1255U-J1........................................................................................................12
Figure 5 : LED Operation Status..........................................................................................................13
Figure 6 : Bluetooth Connection Flow..................................................................................................15
Figure 7 : Authentication Procedure.....................................................................................................18
Figure 8 : ACR1255U-J1 APDU Flow ..................................................................................................35
Figure 9 : ACR1255U-J1 Escape Command Flow ..............................................................................36
List of Tables
Table 1 : Symbols and Abbreviations.....................................................................................................5
Table 2 : Estimated Battery Lifespan....................................................................................................10
Table 3 : USB Interface Wiring.............................................................................................................10
Table 4 : ACR1255U-J1’s Bluetooth Service........................................................................................16
Table 5 : ACR1255U-J1 Service Handles and UUID Information List .................................................16
Table 6 : Command Code Summary....................................................................................................20
Table 7 : Response Code Summary ....................................................................................................20

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Table 8 : Summary of Mutual Authentication Commands....................................................................29
Table 9 : Mutual Authentication Error codes ........................................................................................33
Table 10 : MIFARE® Classic 1K Memory Map ....................................................................................43
Table 11 : MIFARE® Classic 4K Memory Map ....................................................................................44
Table 12 : MIFARE Ultralight® Memory Map.......................................................................................44

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1.0.Introduction
ACR1255U-J1 Bluetooth® NFC Reader acts as an interface for the communication between a
computer/mobile device and a contactless smart card or NFC-enabled device. It establishes a uniform
interface from the computer/mobile device to the smart card for a wide variety of cards. By taking care
of the card’s particulars, it releases the computer software programmer from being responsible with
smart card operations’ technical details, which in many cases, are not relevant to the implementation
of a smart card system.
1.1. Symbols and Abbreviations
Abbreviation Description
ATR Attribute Request and Attribute Response
DEP Data Exchange Protocol Request and Data Exchange Protocol Response
DSL Deselect Request and Deselect Response
PSL Parameter Selection Request and Parameter Selection Response
RLS Release Request and Release Response
WUP Wakeup Request and Wakeup Response
DID Device ID
BS Sending bit duration
BR Receiving bit duration
PP Protocol Parameters
Table 1: Symbols and Abbreviations

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2.0.Features
•USB 2.0 Full Speed Interface
•Bluetooth Smart Interface
•Plug and Play – CCID support brings utmost mobility
•USB Firmware Upgradeability1
•Smart Card Reader:
oBuilt-in antenna for contactless tag access, with reading distance of up to 60 mm
(depending on tag type)
oSupports ISO 14443 Part 4 Type A and B cards
oSupports MIFARE® and MIFARE® DESFire®
oSupports FeliCa
oSupports ISO 18092 Tags (NFC Tags)
oBuilt-in anti-collision feature (only one tag is accessed at any time)
oNFC Support:
Card reader/writer mode
Card emulation mode
oSupports AES-128 encryption algorithm
•Application Programming Interface:
oSupports PC/SC
oSupports CT-API (through wrapper on top of PC/SC)
•Supports Android™ 4.3 and later2
•Supports iOS 5.0 and later3
•Built-in Peripherals:
oTwo user-controllable bi-color LEDs
oUser-controllable buzzer
•Compliant with the following standards:
oEN60950/IEC 60950
oISO 18092
oISO 14443
oBluetooth® Smart
oPC/SC
oCCID
oCE
oFCC
oRoHS 2
oREACH
oVCCI (Japan)
oMicrosoft® WHQL
1Applicable under PC-linked mode
2Uses an ACS-defined Android Library
3Uses an ACS-defined iOS Library

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3.0.System Block Diagram
Figure 1: ACR1255U-J1 Architecture
ACR1255U-J1
NFC
Antenna
MCU
Bluetooth
Mobile
device or
Computer
LEDs Buzzer
Bluetooth
Module
Switch
Re-chargeable battery
USB
Computer
NFC

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For USB communication architecture, the protocol between ACR1255U-J1 and other devices follow
the CCID protocol. All communications for NFC are PC/SC–compliant.
Figure 2: ACR1255U-J1 USB Communication Architecture
ACR1255U-J1 PCSC
NFC Interface
USB Interface
(CCID)
PCSC Layer
T=CL & T=1
Emulation
ISO 14443/ISO 18092
Interface
NFC
(Built-in Antenna)
Physical
Interface

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Bluetooth Smart protocol stack architecture is as follows:
GAP Peripheral
Role Profile SIM Access Profile GAP Peripheral Bond Manager
GAP GATT
SMP ATT
L2CAP
HCI
Link Layer
Physical Layer
Figure 3: BluetoothSmart Protocol Stack

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4.0.Hardware Design
4.1. Battery
ACR1255U-J1 uses a rechargeable Lithium-ion battery, which has a capacity of 320 mAh.
4.1.1. Battery charging
Once the battery of ACR1255U-J1 runs out, it may be charged in any of the following modes: OFF,
USB, Bluetooth; as long as it is connected to a power outlet.
4.1.2. Battery life
The battery life is dependent on the usage of the device. Below is an estimate of the battery life
depending on the various work conditions:
Mode Estimated Battery Life
Working Mode 10 hours
Standby Mode 21 hours
OFF Mode 8 years
Table 2: Estimated Battery Lifespan
4.2. Bluetooth Interface
ACR1255U-J1 uses Bluetooth Smart as the medium to pair the device with computers and mobile
devices.
4.3. USB Interface
The micro USB port is used to connect the ACR1255U-J1 to the computer as battery charging port.
This port is also used in order for the ACR1255U-J1 to operate in PC-linked mode.
4.3.1. Communication Parameters
ACR1255U-J1 is connected to a computer through USB as specified in the USB Specification 2.0.
The ACR1255U-J1 is working in full speed mode, i.e. 12 Mbps.
Pin Signal Function
1 VBUS +5 V power supply for the reader
2 D- Differential signal transmits data between ACR1255U-J1 and computer
3 D+ Differential signal transmits data between ACR1255U-J1 and computer
4 GND Reference voltage level for power supply
Table 3: USB Interface Wiring

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4.3.2. Endpoints
ACR1255U-J1 uses the following endpoints to communicate with the host computer:
4.4. NFC Interface
The interface between ACR1255U-J1 and contactless card follows the ISO 14443 or ISO 18092
specifications with certain restrictions or enhancements aimed to increase the practical functionality of
the reader.
4.4.1. Carrier Frequency
The carrier frequency of ACR1255U-J1 is 13.56 MHz
4.4.2. Card Polling
ACR1255U-J1 automatically polls the contactless cards that are within the field. ISO 14443-4 Type A,
ISO 14443 Type B, FeliCa, Topaz, MIFARE, and NFC tags are supported.
4.5. User Interface
4.5.1. Keys
ACR1255U-J1 has 3 keys with locations shown in the figure below:
Key Description
ANT_KEY Wake up from sleep mode
MODEL_KEY Mode selection
UPDATE_KEY Enable boot loader
Control Endpoint For setup and control purpose
Bulk OUT For command to be sent from host to ACR1255U-J1
(data packet size is 64 bytes)
Bulk IN For response to be sent from ACR1255U-J1 to host
(data packet size is 64 bytes)
Interrupt IN For card status message to be sent from ACR1255U-J1 to host
(data packet size is 8 bytes)

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Figure 4: Keys on ACR1255U-J1
4.5.2. Mode Selection Switch
ACR1255U-J1 has three modes: USB, Off and Bluetooth. User can select one mode at a time as a
data transmission interface.
Symbol Switch Active Mode
USB PC-linked
Off No power
Bluetooth Bluetooth
MODEL_KEY
UPDATE_KEY
ANT_KEY

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4.5.3. Status LED
ACR1255U-J1 has two bi-color LEDs to show the various operation statuses, where:
Figure 5: LED Operation Status
Mode Color LED Activity Status
Bluetooth
Mode
Blue
(LED1)
Off Reader is powered off No Bluetooth device paired
Reader is in USB mode
Slow flash v14The paired Bluetooth device is authenticated successfully and
is waiting for instructions
Slow flash v25Bluetooth device is paired, card polling is on and no card is
present
Fast flash Data is being transferred between the reader and paired device
Fast – Slow flash Powered on
Searching for devices to be paired with
On Bluetooth device is paired with the reader
Card is present
Red
(LED2)
Off
Battery is fully charged
Reader is powered off
The voltage of the battery is greater than 3.5 V and no USB
powered is being supplied
Slow flash Low battery
On Battery is charging
USB mode
Green
(LED2)
Off Reader is powered off
Slow flash No card presented and the reader is waiting for instruction
Fast flash There is read/write access between the smart card and reader
On Card is present and the reader is waiting for instruction
Orange6
(LED2) On Device is powered on
4LED is on for 500 ms, off for 500 ms
5LED is on for 200 ms, off for 1800 ms
6Green and Red both turned on
LED1
LED2
•Blue - Bluetooth Status
•Red - Battery Status
•Green – USB

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Mode Color LED Activity Status
Red
(LED1)
Off
Battery is fully charged
Reader is powered off
The voltage of the battery is greater than3.5V and no USB
powered is being supplied
Slow flash Low battery
On Battery is charging
4.5.4. Buzzer
ACR1255U-J1 has a buzzer that is used to notify user of card polling, Bluetooth connection, sleep
mode, and low-battery status.
Buzzer Activity Event
One short beep Card has been detected or removed
One long beep Reader has been powered on

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5.0.Software Design
5.1. Bluetooth Connection Flow
The program flow of the Bluetooth connection is shown below:
Figure 6: Bluetooth Connection Flow
Yes
No
Bluetooth Start
(Reset/Power up)
Successful Connection?
No
Enable Service
Disconnect?
Reset
Power Off
Authentication
Smart Card Operation with Security Channel
Successful Authentication?
Yes
Yes

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5.2. Profile Selection
ACR1255U-J1 is a smart card reader that is designed to use Bluetooth technology as an interface to
transmit data. A customized service called Commands Communication with three pipes is used: one
pipe is used for command request, the second pipe is for command response/card notification, and
third is RFU.
Also, the reader’s current power consumption is significantly greater when the reader is operating in
Bluetooth mode, hence, a standard battery service is used to notify the paired device about the
current battery status. When there is a change in the battery status, the reader will notify the paired
device through a specific pipe. To simplify, the battery levels are divided into three groups: sufficient
battery (≥ 3.78 V), low battery (<3.78 V and ≥ 3.68 V), and no battery (<3.68 V).
Finally, to provide more reader information to the user, a customized Device Information service is
added. This can only be read manually, or by an application request. The characteristics include
Model Number, Serial Number, Firmware Revision, and Manufacturer Name.
Service UUID Pipe
Smart Card
FFF1 Commands Request
FFF2 Commands Response/Card Notification
FFF3 RFU
Battery 2A19 Battery Level
Device Information
2A23 System ID
2A24 Model Number
2A25 Serial Number
2A26 Firmware Revision
2A27 Hardware Revision
2A29 Manufacturer Name
Table 4: ACR1255U-J1’s Bluetooth Service
Attribute Name UUID Handle
DeviceName 2A00 03h
Send(Reader →Paired device) 8002 0Bh
Receive(Paired device →Reader) 8003 0Eh
CardStatus 8004 10h
BatteryLevel 2A19 14h
Manufacturer 2A29 18h
SerialNumber 2A25 21h
FW_Version 2A26 1Bh
ModelNumber 2A24 1Eh
Table 5: ACR1255U-J1 Service Handles and UUID Information List

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5.3. Authentication
Before any sensitive data can be loaded into ACR1255U-J1, the data processing server must be
authenticated by ACR1255U-J1 for the privilege to modify the secured data inside reader. In
ACR1255U-J1, a mutual authentication method is being used.
An authentication request is always initiated by either the data processing server or the bridging
device, which will then trigger ACR1255U-J1 to return a sequence of 16 bytes of random numbers
(RND_A[0:15]). The random numbers are encrypted with the Customer Master Key currently stored in
ACR1255U-J1 using the AES-128 CBC ciphering mode before being sent out from ACR1255U-J1.
The bridging device must pass this sequence of encrypted random numbers to the data processing
server, which will then undergo AES-128 CBC cipher mode decryption using the Customer Master
Key that is being used in the data processing server (which should be the same as the one that is
being used in ACR1255U-J1 and should be kept securely by the customer). The 16 bytes of
decrypted random numbers from ACR1255U-J1 is then padded to the end of another 16 bytes of
random numbers generated by the data processing server (RND_B[0:15]). The final sequence of 32
bytes of random numbers (RND_C[0:31]), that is:
RND_C[0:31] = RND_B[0:15] + RND_A[0:15],
will undergo decryption operation with the Customer Master Key being used in the server and the final
output data is sent to ACR1255U-J1 through the bridging device using an authentication response
message.
When ACR1255U-J1 receives the authentication response message, the message data will undergo
an encryption operation using its own Customer Master Key and will be converted back to the normal
32 bytes of random numbers. In theory, the first 16 bytes of random numbers should be equal to
RND_B[0:15] and are generated by the data processing server while the other 16 bytes should be
equal to RND_A[0:15] and are originally generated by ACR1255U-J1.
ACR1255U-J1 will first compare if RND_A[0:15] is the same as the original version. If it is the same,
then the data processing server is authenticated by ACR1255U-J1. ACR1255U-J1 will then encrypt
RND_B[0:15] obtained using the Customer Master Key and the feedback to the data processing
server through the bridging device using the answer to the authentication response message.
Upon receiving the answer to the authentication response message, the data processing server will
decrypt the data contained in the message and check if the 16 bytes of random numbers are all equal
to those originally generated RND_B[0:15]. If they are the same, then ACR1255U-J1 is authenticated
by the server. At this moment, the whole authentication process is completed and sensitive data can
be injected into ACR1255U-J1.
After successful authentication, a 16-byte Session Key is generated in both ACR1255U-J1 and the
data processing server. The Session Key (SK[0:15]) is obtained by padding the first 8 bytes of RND_B
at the end of the first 8 bytes of RND_A, that is:
SK[0:15] = RND_A[0:7] + RND_B[0:7]
All sensitive data leaving out of the Secured Data Processing Server must be encrypted with this
Session Key using the AES-128 CBC ciphering mode. Thus, even if the encrypted data may be
captured in the bridging mobile device, it is still very difficult to retrieve the original sensitive data
without any prior knowledge of the Customer Master Key.

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For better illustration, please refer to figure below (the picture below has omitted the bridging device
for simplicity and better illustration):
Figure 7: Authentication Procedure
Below is a summary of the above mentioned steps:
1. The data processing server/bridging device initiates an authentication request from
ACR1255U-J1 by issuing an authentication request message.
2. Upon receiving the authentication request message, ACR1255U-J1 will generate 16 bytes of
random numbers (RND_A[0:15]). The whole 16 bytes of data is encrypted with the Customer
Master Key currently being used by ACR1255U-J1.
3. The encrypted version of RND_A[0:15] is then transferred to the data processing server
through the answer to the authentication response message.
4. The data processing server will decrypt the data received to recover RND_A[0:15].
5. The data processing server will generate another 16 bytes of random numbers (RND_B[0:15]).
RND_A[0:15] will be padded to the end of RND_B[0:15] to form a sequence of 32-byte
random numbers (RND_C[0:31] = RND_B[0:15] + RND_A[0:15]). All the 32 bytes of random
numbers will undergo a decryption process with the Customer Master Key currently being
used in the server.
6. The final output data from the encryption process will be transferred to ACR1255U-J1 through
the authentication response message.
7. In ACR1255U-J1, an encryption process will be performed on the received data to recover the
32 bytes of random number. ACR1255U-J1 will check the result RND_A[0:15] to see if they
are the same as the original ones. If not, the authentication process will be terminated.
8. ACR1255U-J1 will encrypt the resultant RND_B[0:15] with the Customer Master Key. At the
same time, 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.
1.
Send authentication
request message
3.
Answer to the request
message
2
6.
Send authentication
response message
7
8
9.
Answer to the
authentication response
message
4
5
10
Transmitted
through the
bridging device

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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 + Datablock + 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:
CmdMessageType + Length + 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.

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Response
HID Frame Length (bytes) Description
RspMessagType 1 Commands
Length 2 Data length
Slot 1 Default value: 00h
Seq 1 Sequence
Slot Status/Param 1 Slot Status/Parameter
Checksum 1 Checksum
Data 0-N Data
Data checksum is used in detecting errors that may have been introduced during wireless data
transmission. To calculate the data checksum: XOR { RspMessageType, Length, Slot, Seq,
SlotStatus/Param, Data }.
Example: 62010063 => Checksum = 63h
5.6. Bluetooth Communication Protocol
ACR1255U-J1 communicates to the paired device using the Bluetooth interface with a predefined
protocol. The protocol is similar to the formats of the CCID Command Pipe and Response Pipe.
Command Mode Supported Sender Description
62h Authenticated Paired device PICC Power On
63h Authenticated Paired device PICC Power Off
65h Authenticated Paired device Get Card Status
6Fh Authenticated Paired device Exchange APDU
6Bh Authenticated Paired device Escape Commands
Table 6: Command Code Summary
Command Mode Supported Sender Description
80h Authenticated Reader Response to Data Block
81h Authenticated Reader Response to Slot Status
83h Authenticated Reader Response to Escape Command
50h Authenticated Reader Notify Card Status
51h Authenticated Reader Response to Hardware Error
Table 7: Response Code Summary