System and method for radio frequency tag group select

A method of selecting subgroups of a group of radio frequency tags comprising the steps of:

• a. sending a radio signal from a base station to a plurality of radio frequency tags, the radio signal carrying one or more commands, the commands each being one of a SELECT command and an UNSELECT command, each of the commands defining one or more conditions, the tags each having a radio frequency communications component for receiving the command and a tag memory with tag fields;
• b. sending one or more SELECT commands on the radio signal;
• c. comparing a selection condition on the SELECT commands to a select tag data value in the tag memory of each of the tags, and moving one or more of the tags to a SELECTED state if the select tag data value meets the selection condition, the tags moved to the SELECTED state being in a first selected subgroup of tags from the group of tags, and the tags in the first selected subgroup having data in their respective tag memory that meets the selection condition;
• d. sending one or more UNSELECT commands on the radio signal from the base station to the plurality of radio frequency tags, the UNSELECT commands defining an unselection condition;
• and
• e. comparing the unselection condition on one of the UNSELECT commands to an unselect tag data value in the tag memory of each of the tags in the first selected subgroup, and moving one or more of the tags in the first selected subgroup out of the SELECTED state if the unselect tag data value meets the unselection condition, the remaining tags in the SELECTED state being a second selected subgroup of tags, the tags in the second selected subgroup having data in their respective tag memories that meet the selection conditions and do not meet the unselection conditions.

A radio frequency transponder comprising:

• a radio frequency component for receiving one or more frequency signals, the radio frequency signals carrying one or more commands, the commands having a command type, a command function, a tag memory address value, and a command data, the command type capable of being any one of a SELECT command and an UNSELECT command;
• a tag memory with a tag memory address and tag memory data;
• a tag control logic performing the command function, the command function specifying a comparison with one or more comparison conditions;
• and
• a tag compare function performing the comparison between the tag memory data located in the tag memory address specified by the tag memory address value and the command data, if the comparison conditions are satisfied, the tag control logic causing the tag to move to a SELECTED state if the command type is a SELECT command the tag control logic causing the tag to move to an UNSELECTED state if the command type is an UNSELECT command.