Patent attributes
An RFID transponder for use in a security system based upon RFID techniques. The RFID transponder may be connected to an intrusion sensor. Example intrusion sensors are magnetically sensitive relay or LED detectors. The RFID transponder may also be connected to a passive infrared sensor. The RFID transponder can contain a battery, and the battery can be recharged by receiving and converting RF energy transmitted by the RFID reader. The security system also supports RFID transponders that may be carried by persons or animals, of that may contain a button used to signal an event such as an emergency. The RFID transponder typically uses backscatter modulation for responses, and can accept various modulation techniques for inbound wireless communications. The RFID transponder only responds when permitted.