Arinc Data Format - Access ATB420 Series Service Manual

Access keyboards ATB 420/421 Multi-Function Keyboard Product Specification and Service Guide
<SOD1><STX><ESC> 045H <ETX><EOD1>
5.6

ARINC Data Format

In ARINC format, RS232 serial data from the ATB420/421 is transmitted in the form of blocks with
the following generalised format.
<STX><logical link data ..up to 1024 bytes of data..<ETX><CRC-16>
MNEMONIC HEX VALUE
STX 02
ETX 03
DLE 10
CR 0D
ESC 1B
Any character in logical link data that is less than 20 Hex will be preceeded by a DLE on transmit.
On the received side the DLE is stripped and the following character value is not checked for
control but simply buffered. Inserted DLE's are included in the 1024 byte count maximum size.
CRC-16 is calculated on the whole data link message, STX through ETX inclusive. All DLE
characters are omitted from the CRC calculation except true DLE characters sent as DLE DLE and
in this case only the first character is omitted.
5.6.1 Logical Link Data Format
<DID><application data>
Where DID = MUSE Device Identifier with 2 parts
device type DTYP defined in high order 4 bits
device type DNUM defined in low order 4 bits
DTYP
(device type)
1010 - MSR
1011 - BCR
1100 - OCR
5.6.2 Application Layer – MSR, BCR and OCR Data Format
When the ATB420/421 formats data read from MSR is the following data structure is used
<DOC><BID><one block of data><EOB>
<BID><one block of data> etc
The DOC (Document Identifier) is defined as follows:
DOC (binary)
00110000
00110001
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DESCRIPTION
START OF TEXT. This character signals the START of BLOCK
END OF TEXT. This character signals the END of a
BLOCK
Date Link Message Transparency Prefix
Carriage Return
Escape
DNUM
(device number)
0001 – Device # 1 of DTYP
0010 – Device # 2 of DTYP
0011 – Device # 3 of DTYP
Type identified
Default
MSR Credit Card
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