An electronic tag (10) receives a data message (18) that has a wake-up section (20) followed by a session section (22). The interrogation signal which carries the data message encodes the wake-up section (20) differently from the session section (22). A power manager (28) decodes the wake-up section...http://www.google.com/patents/US5606313?utm_source=gb-gplus-sharePatent US5606313 - Low power addressable data communication device and method
