User's Guide

CHAPTER 2 RFID OVERVIEW
 Transmitters. A transmitter tag can broadcast a message into the
environment even if there is no reader active nearby to “hear” it. This tag
is like a telephone can ring even when no one is home to answer it.
MY NAME IS GORT...MY
NAME IS GORT...MY NAME...
TAG
Active tags (transmitters) contain their own little radio stations and can transmit
messages even the absence of a reader.
 Transponders. To conserve power, or to minimize RF noise pollution,
some active/transmitter tags may be configured to “go to sleep” or enter
a quiescent or lower-power state when not being interrogated. When a
reader enters the area, it then transmits a signal to “wake up” all the tags
in that area. Each tag thus only transmits in response to the reader’s
command. This type of active tag is called a “transmitter/responder” or
“transponder.”
ZZzzz ZZzzz Hello? ZZzzz
ZZzzz Hello? ZZzzz ZZzzz
TAG
NANOSCANNER READER USER GUIDE • DOC # 8101001-000A 10
© 2002 Alien Technology™
Active tags that are considered transponders (transmitter/responders) go into a
quiescent or low power state (“sleep”) until awakened by a reader.
READER
MY NAME IS GORT...MY
NAME IS GORT...MY NAME...
Wake up
and speak!
TAG