Operation of RFID tags
There are 2 different principles associated with the RFID tags. Passive tags and active tags, the active tags are working with a builtin energy source, this means the lifetime of these tags are limited, advantage is that the maximum reading distance is far greater. Libraries use the passive tags, this means that an external power source is responsible for the workings of the tag. That source comes from the tag reader. Which sends out a signal of 13.56 Mega Hertz. This signal is absorbed by the tag and converted into energy, with this energy the chip inside the tag activates and in turn uses its antenna to disrupt the signal from the tag reader. These disturbances are caught by the reader and converted into digital signals. Writing a tag goes the other way around, the chip captures the signals that the tag reader sends, they are translated into digital signals that are stored in the chip. Thus writing a tag requires more energy then reading a tag.
There are a number of different techniques in the RFID library industry.
- ISO 15693 I·CODE SLI : this is the most commenly used RFID label in the dutch library industry. It contains 27 blocks, each with 4 Bytes capacity, the blocks 0 through 9 are defined in the General Set of Requirements.
- I·CODE 1 : this type of RFID label is used in small libraries, the label was used as a pilot project to test RFID. The responce time of this label is considerably slower then that of the I·CODE SLI.
