Multi-mode identification system

摘要

A multi-mode identification system is comprised of readers and tags wherein a reader (100) in the proximity of and inductively coupled (100) to a tag (200) interrogates and obtains a response from the tag (200) in accordance with a specified process if the tag (200) belongs to a certain class of tags. The response consists of an identification code unique to the tag (200) together with the data supplied by sensors (270, 275) incorporated within the tag (200). Communication between tag (200) and reader (100) is accomplished by a reader (100) establishing a reversing magnetic field in the vicinity of a tag (200) and the tag (200) varying its absorption of power from the field in accordance with the information to be transmitted. The reader (100) detects these variations in power absorption and extracts from these variations the information transmitted by the tag (200).