User's Guide Part 2

CHAPTER 6 READER-HOST PROTOCOL EXTENSIONS FOR BATTERY POWERED BACKSCATTER TAGS
CHAPTER 6
ReaderÙHost Protocol Extensions for Battery
Powered Backscatter Tags
The Reader <–> Host protocol detailed in Chapter 5 is a text-based
communications protocol for configuring and operating the entire family of Alien
Nanoscanner RFID readers. This chapter details extensions to this standard
protocol that directly address the extended functionality of the Battery Powered
Backscatter tags running at 2450Mhz.
Introduction
The Battery Powered Backscatter readers fully support the Class I protocol as
described in chapter 5 of this document. In addition to the basic Class I
command set, these readers also support extra commands especially designed
to address the enhanced functionality of the Battery Powered Backscatter tags.
These extra commands fall into one of five categories:
Masks
All commands aimed at Battery Powered Backscatter tags require the setting of a
mask, which directs the commands only at the tags who’s ID matches the mask.
This mechanism allows commands to be sent to one specific tag, a selective
group of tags or the whole field of tags.
Tags
The tag commands are used to explicitly communicate with a tag, to either
interrogate its features and functionality, or its ID.
Memory
The Battery Powered Backscatter tags support a read-write on-board memory
typically in the range of 4K bytes to 16K bytes. The memory commands
described in this document allow the tag memory to be read and written in
discrete blocks via RF communication.
Sensors
The Battery Powered Backscatter tags can optionally support the use of on-
board sensors such as temperature or vibration sensors. The sensor commands
can be used to interrogate and control the use of these on-board devices.
Logging
If a tag is equipped with one or more sensors, they can be instructed to
autonomously log data to tag memory even in the absence of an RF field. The
logging commands are the interface to this functionality.