User Manual

Chapter 8 System Parameters and Comm ands
- 134 - Hi-G-Tek Ltd. Micro electro nic s & A sset Tra cking Techno logy
The Reader Interrogation Header is composed of many short segments that
contain indications of when the command starts. This way, when a
DataSeal receives the Reader Interrogation Header, it doesn't have to keep
its receiver open until the command, rather, it goes to sleep exactly until the
command.
Choosing the best Tw and Th w should take in account the following facts:
 Small Tw and Th w will improve response times for RF command. Big
Tw and Th w will cause lengthily interrogations.
 Small Tw and Th w will shorten the battery lifetime of the DataSeals.
Big Tw and Th w will lengthen it.
8.1.2 Addressing Types
In general, there are 3 types of commands that are distinguished by the way
they indicate which DataSeal or DataSeals will respond:
1. Addressed (AMM): These commands specify exactly one Seal ID.
Only the DataSeal with that Seal ID responds.
2. Multi Addresse d (BMM List): These commands specify a list of Seal
IDs. The DataSeals in the list respond in the same order as they appear
in the list. This way there are no RF collisions between the responses of
t he different Dat aSeals. Mult i Addressed commands wit hout argument s
can contain up to 8 Seal IDs in the list. Currently, the only Multi
Addressed command with arguments is the Multi Addre ssed Ve rify,
which can contain up to 7 Seal IDs.
3. Broadcas t (BMM): These commands are aimed for all the DataSeals
that receive the DataReader's transmission. There are actually 2 types
of broadcast commands: commands without response and commands
with response. The commands that do not wait for a response from the
DataSeals are the simplest, in the way that after the DataReader has