Patent ID: 7319397

Claim:
An RFID monitoring device arrangement comprising a first RFID monitoring device and a second RFID monitoring device for monitoring said first RFID device, said first RFID monitoring device comprising: a memory having unique identifying information stored therein and having codes representing at least two different transmitter power levels stored therein; an antenna for transmitting and/or receiving electromagnetic signals; a modulator coupled to said memory for modulating the unique identifying information and the transmitter power level codes stored in said memory; and a transmitter coupled to said modulator and to said antenna for transmitting at least two messages via said antenna, wherein each of the at least two messages includes the modulated unique identifying information and a modulated different one of the transmitter power level codes, wherein the power level of said transmitter is controlled responsive to the power level code to correspond to the power level represented by the power level code in each transmitted message when each message is transmitted; whereby the transmitter power level is different for each of the messages and corresponds to the power level code contained in each of the messages transmitted by said first RFID device; and said second RFID monitoring device comprising: a receiver for receiving messages transmitted by said first RFID device, each message including the identifying information and the power level code representing the power level at which the message is transmitted; a processor for receiving the received messages and for processing the information therein, wherein said processor decodes the identifying information and the power level code from each received message for associating received messages from said first RFID device and the power level thereof, said processor providing from the messages received from said first RFID device and the power level thereof an indication of a condition; and a transmitter for relaying messages received from said first RFID device, the indication of a condition, or the messages received from said first RFID device and the indication of a condition, to a remote location, whereby the first RFID device is monitored by the second RFID device.