There are vertain rules for encoding the RFID tags.
At the moment , RFID tags follow the EPC coding rules. The full name
of EPC is Electronic Product code.
The carrier of EPC is an RFID electronic tag, and the information is transmitted through the Internet. EPC aims to establish a global, open labeling standard for each item,
enabling tracking and tracing of individual products on a global scale, there by effectively improving supply chain management and reducing logistics costs. EPC is a complete,
complex, integrated system.
The product electronic code (EPC code) is a new generation product coding system introduced by the international bar code organization. The original product barcode is only the
encoding of the product classification. The EPC code is a globally unique code for each item, and the EPC encodes a 96-bit (binary) encoding system. The 96-bit EPC code can be
assigned to 268 million companies. Each company can have 16 million product categories. Each product has 68 billion independent product codes. The image says that it can give
each rice on the earth a unique name.
TID and EPC different
The TID number of UHF is only can read but not can be changed.So TID number is the only unique number in the global.
But EPC can be changed. That is why EPC can be same in different RFID tags, but each tags with different TID number. It is unique in the world.
RFID-EPC- EPCIS relations
1. The carrier of the EPC is the RFID tag in the RFID system. The product electronic code can only be read out if it is stored in the RFID chip.
2. The most simplified version of the EPC system is the EPC code + RFID tag + communication network, which is a complex, comprehensive and integrated system, including RFID, EPC
coding, network, communication protocols, etc. RFID is only one of the components.
3. EPC is one of the application areas of RFID technology, and only specific low-cost RFID tags are suitable for EPC systems.
4. EPCIS provides standard specifications and data interfaces for EPC exchange. Without EPCIS, information on goods represented by the EPC cannot be communicated between trading
partners around the world.
5. EPC is similar to a bar code, except that the bar code is the printed version of the paper (or other material, mainly determined by the product packaging), and the EPC is the
electronic data stored in the RFID chip.
6. The EPCIS specification manages the EPC. The EPC information is stored in the RFID tag and read by the RFID reader.
7. If the product uses EPC, then every item in the world will have a unique EPC. For example, the barcode of 500ML Master Kong Jasmine Tea is the same, and if EPC is used, even
if it is a similar product, each product has a unique EPC.