User Manual

Chapter 6 System Overview
Hi-G-Tek Ltd. Micro electronics & Asset Tracking Technology - 81 -
Even though all the User Data is simply a flat memory segment, the lowest
53 bytes are of special meaning for the DataTerminal. If you're using or
considering to use a DataT erminal in your system someday in the future,
you should use these 53 bytes in a way that is compatible with the
DataTerminal. The DataT erminal uses the first 53 bytes as follows:
6.6.2.1 The User Data portion used by the DataTerminal
The DataT erminal is capable of viewing and editing 48 bytes (addressed 5
– 52) of the User Data as a structure of ASCII fields. This structure has to
be defined first by t he user, using a special P C soft ware provided wit h t he
DataTerminal, and then uploaded to the DataTerminal. The structure
definition includes the labels and sizes of the fields and is assigned an
identifier (called UDT ), and a version number. When the user writes User
Data using the DataTerminal, the DataT erminal always stores this identifier
and version number in address 0, and the date and time when the data was
written, in addresses 1-4.