User's Manual

Page 5 of 9
U
niversal Terminal UT1
Version 0.03 Oct 2008
\
ACR122S PC-linked Contractless Smart Card Reader
7.0 Serial Interface (CCID-liked FRAME Format)
Communication setting: 9600 bps, 8-N-1
The communication protocol between the Host and ACR122S is very similar to the CCID
protocol.
STX
(0x02)
Bulk-OUT Header APDU Command
Or
Parameters
Checksum ETX
(0x03)
1 Byte 10 Bytes M Bytes
(If applicable)
1 Byte 1 Byte
STX
(0x02)
Status Checksum ETX
(0x03)
1 Byte 1 Byte 1 Byte 1 Byte
STX
(0x02)
Bulk-IN Header APDU Response
Or
abData
Checksum ETX
(0x03)
1 Byte 10 Bytes N Bytes
(If applicable)
1 Byte 1 Byte
Checksum = XOR {Bulk-OUT Header, APDU Command or Parameters}
Checksum = XOR {Bulk-IN Header, APDU Response or abData}
In general, we would make use of three types of Bulk-OUT Header.
• HOST_to_RDR_IccPowerOn: To activate the SAM interface. The ATR of the SAM will be
returned if available.
• HOST_to_RDR_IccPowerOff: To deactivate the SAM interface.
• HOST_to_RDR_XfrBlock: To exchange APDUs between the Host and ACR122S-PM.
#The SAM interface must be activated in order to use the Contactless interface and
Peripherals. In short, all the APDUs are exchanged through the SAM Interface.
Similarly, two types of Bulk-IN Header are used.
• RDR_to_HOST_DataBlock: In response to the “HOST_to_RDR_IccPowerOn” and
“HOST_to_RDR_XfrBlock” Frames.
• RDR_to_HOST_SlotStatus: In response to the “HOST_to_RDR_IccPowerOff” Frame.
ACR122S Command Frame Format
ACR122S Status Frame Format
ACR122S Response Frame Format
HOST_to_RDR=Host Controller->ACR122S
RDR=ACR122S,HOST=Host Controller.
RDR_to_HOST=ACR122S->Host Controller