The physical tag is used for indicating the brief sign item name, weight, volume and use of information. Has the traditional printing label and the modern bar code printing label.

Network (tag) is an Internet content organization, is a very strong correlation between keywords, it helps people easily describe and classify content, in order to facilitate retrieval and sharing, tag has become Web 2.0 important elements.

Electronic label, also known as RFID, transponder, data carrier; reader also known for readout, scanner, read head, communicator, read and write device (depending on the electronic label can be wireless data rewrite). The space of the radio frequency signal is coupled between the electronic tag and the reader through the coupling element; in the coupling channel, according to the time sequence relation, the energy transfer and data exchange are realized.