Table of Contents - APTAStandards.com

Field Name Description
reading the SamId and DeviceId data arriving in
the header.
Udsn UD sequence number. The UDSN will reset back
to 0 when it increments past 0xFFFFFFFF.
Transac tion Status Indicates if the UD transaction is a normal
or test
transaction. Test transactions are ignored.
UdTyp e Main UD group that defines the type of
transaction.
UdSubtype Sub UD groups within UD.
4.8.3.3 Variant Data
Variant
Data consist of a group of selected data structures to form the body of a
message. The message type determines the kind and quantity of data structures to exist
in a message.
For example a “Product Purse Use” Message contains the following data
structures
from the Exhibit 4.8-2:
• SysComHdr_t
• SysPiccCom_t
• SysApplicationCom_t • DevUdPurseCommonHdr_t
• SysFinDetails_t
• DevUdPurseLavHdr_t • SysSecurityHdr_t 4.8.4 Message Types
As in the TransLink system, ERG specifications break transaction data into types and
subtypes to provide the system with a unique level of message identification.
Messages fall into one of the following
seven main transaction types (UdType), as
illustrated
in Exhibit 4.8-5. Each transaction group contains further message types
(UDSubType)
within them.
Page 61