<P> RFID tags contain at least three parts: an integrated circuit that stores and processes information and that modulates and demodulates radio - frequency (RF) signals; a means of collecting DC power from the incident reader signal; and an antenna for receiving and transmitting the signal . The tag information is stored in a non-volatile memory . The RFID tag includes either fixed or programmable logic for processing the transmission and sensor data, respectively . </P> <P> An RFID reader transmits an encoded radio signal to interrogate the tag . The RFID tag receives the message and then responds with its identification and other information . This may be only a unique tag serial number, or may be product - related information such as a stock number, lot or batch number, production date, or other specific information . Since tags have individual serial numbers, the RFID system design can discriminate among several tags that might be within the range of the RFID reader and read them simultaneously . </P> <P> RFID systems can be classified by the type of tag and reader . A Passive Reader Active Tag (PRAT) system has a passive reader which only receives radio signals from active tags (battery operated, transmit only). The reception range of a PRAT system reader can be adjusted from 1--2,000 feet (0--600 m), allowing flexibility in applications such as asset protection and supervision . </P> <P> An Active Reader Passive Tag (ARPT) system has an active reader, which transmits interrogator signals and also receives authentication replies from passive tags . </P>

When using rfid what is an arpt (active reader passive tag)
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