Designed to be stored on an RFID tag, the Electronic Product Code (EPC) is a unique number that identifies a specific item in the supply chain. The EPC can be associated with dynamic data such as the origination point of an item or the date of its production. Much like a Global Trade Item Number (GTIN) or Vehicle Identification Number (VIN), the EPC is key to unlocking the power of the information systems that are part of the EPCglobal Network™.
The Electronic Product Code (EPC) is designed as a universal identifier that provides a unique identity for every physical object anywhere in the world, for all time. Its structure is defined in the EPCglobal Tag Data Standard, which is an open standard freely available for download from the website of EPCglobal, Inc.. The canonical representation of an EPC is a URI, namely the ‘pure-identity URI’ representation that is intended for use when referring to a specific physical object in communications about EPCs among information systems and business application software. The EPCglobal Tag Data Standard also defines additional representations of an EPC identifier, such as the tag-encoding URI format and a compact binary format suitable for storing an EPC identifier efficiently within RFID tags (for which the low-cost passive RFID tags typically have limited memory capacity available for the EPC/UII memory bank). The EPCglobal Tag Data Standard defines the structure of the URI syntax and binary format, as well as the encoding and decoding rules to allow conversion between these representations. The EPC is designed as a flexible framework that can support many existing coding schemes, including many coding schemes currently in use with barcode technology. EPC identifiers currently support 7 identification keys from the GS1 system of identifiers, as well as a General Identifier and EPC identifiers that can be used for encoding supplies to the US Department of Defense.
EPCs are not designed exclusively for use with RFID data carriers. They can indeed be constructed based on reading of optical data carriers, such as linear bar codes and two-dimensional bar codes, such as Data Matrix symbols. The ‘pure identity URI’ canonical representation of an EPC is agnostic to the data carrier technology that was used to attach the unique identifier to the individual physical object.
The EPC is designed to meet the needs of various industries, while guaranteeing uniqueness for all EPC-compliant tags. Some of the existing GS1 identification keys (such as the Global Returnable Asset Identifier (GRAI)) already provide for unique identification of individual objects. However, the Global Trade Item Number (GTIN) only identifies the product type or stock-keeping unit (SKU) rather than an individual instance of a particular product type. To ensure that an EPC always uniquely identifies an individual physical object, in the case of a GTIN, the EPC is constructed as a serialised Serialised Global Trade Item Number (SGTIN) by combining a GTIN product identifier with a unique serial number.
Both the Universal Product Code and EAN_13 identifiers that are still found on many trade items can be mapped into a 14-digit GTIN identifier, by padding to the left with zero digits to reach a total of 14 digits. An SGTIN EPC identifier can therefore be constructed by combining the resulting GTIN with a unique serial number and following the encoding rules in the EPCglobal Tag Data Standard.