Before knowing how to read RFID tags it one must know what RFID tags are. RFID is the acronym for Radio-Frequency Identification and are small, but extremely useful electronic devices that carry a chip and can withstand up to 2000 bytes of data. These tags are extensively used today for the purpose of tracking people, animals, and goods in a large number of sectors such as logistics, transport, pharmaceuticals, hospitality, agriculture, automobile and farming, etc. 

In order to understand how to read RFID tags, one must first understand the classification of it in two categories- Active tags and Passive Tags. Active tags are those tags which operate by the use of batteries. After the batteries discharge, they can be either replaced or recharged for further use. Active tags have the ability to broadcast its own signal in order to transmit the information stored on its microchips. These tags operate on ultra high frequencies.

Passive tags do not use batteries and have an indefinite life expectancy. These tags operate on Low frequencies, high frequencies and ultra high frequencies. There is another category of RFID tags which is called the BAP RFID system which is a sub category of Passive tags that have an outstandingly productive attribute. Though these RFID BAP tags do not have their own transmitters unlike transponders but they have a battery that acts like an integrated source of power for the RFID chip that has the capability of capturing energy from the reader. 

The question of how to read RFID tags is answered as follows. These tags are broken up into 4 frequency groups- Low Frequency, High Frequency, Very High Frequency and Ultra High Frequency.

1.Low Frequency Bands (LF) - LF bands cover a frequency range from 30 KHz to 300 KHz. The usual range for LF RFID system is 125 KHz.

2.High Frequency Bands (HF) - These tags operate between the frequencies 3 and 30 MHz and most of the HF RFIDs operate at 13.56 MHz.

3.Very High Frequency Bands (VHF) - The VHQ bands cover ranges from 30 MHz to 300 MHz. Though these tags are not used for RFID.

4.Ultra High Frequency Bands (UHF) - These are the tags that support high frequencies ranging from 300 MHz to 3 GHz. For RFID, the usual ranges are 868 MHz and 915 MHz.