User Guide

Table Of Contents
Gen2 Tag Commands
100
Tag Singulation/Select Functionality
Many of the Gen2 tag commands now support the ability to singulate a specific tag or
inventory only tags matching a defined criteria, i.e. matching on values in the EPC, TID
and User Memory banks.
Select Algorithm and Parameters
The algorithm used to perform a Gen2 Select and its impact on subsequent Gen2 Query
operations on a population of tags is determined by several user defined settings which
either correspond directly to or are used to determine the various Gen2 Select and Query
parameters as defined by the EPCGlobal Gen2 v1.2 Specification. The current user
controlled options are:
Gen2 Session (User Controlled)
This setting determines which tag inventory flag is altered when a tag responds to a Gen2
Query (each flag has a unique persistence profile, as defined by the Gen2 Specification).
The value of Gen2 Session is set using the
Set Protocol Configuration (9Bh) command.
The supported values are 0, 1, 2, or 3.
Select Invert (User Controlled)
This setting is used to determine the Gen2 Action value sent in the Gen2 Select
command. The value of Select Invert is defined using bit 3 of the Select Option field in the
Tag Singulation Fields. The supported values are:
0 (False) - Tags which match the Select criteria are to respond. Set Gen2
Action=0.
1 (True) - Tags which DO NOT match the Select criteria are to respond. Set Gen2
Action=4.
The settings specified for Gen2 Session and Select Invert determine the settings within
the Select command which is sent before the corresponding Gen2 Query and the settings
in the subsequent Gen2 Query(s). These implicit settings used by the Gen2 Select are:
Gen2 Action (defined by Select Invert)
This parameter can be one of 8 values, as defined by the Gen2 specification, which
determine which of 4 possible flag actions (assert, de-assert, negate, or leave alone) will
be done if the criteria matches and, similarly, which of the 4 possible flag actions will be
done if the criteria does not match. Only two values are currently used: