User's Manual

CHAPTER 7 READER-HOST PROTOCOL EXTENSIONS FOR BATTERY POWERED BACKSCATTER TAGS
NANOSCANNER READER USER GUIDE • DOC # 8101029-000 REV A 88
© 2003 Alien Technology™
CHAPTER 7
ReaderHost Protocol Extensions for Battery
Powered Backscatter Tags
The Reader <–> Host protocol detailed in the previous chapter 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 the previous chapter 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
In order to address a single tag with any of the following commands, a suitable
Mask must be set. Please see the description of the Mask command in the
previous chapter of this document.
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 can optionally 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 this 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 and on-board memory, 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.