EPC Scheme & Barcode Glossary

Frequency bands

LF RFID (125–134.2 kHz)Low Frequency – animal identification, access control, vehicle immobilisers.HF RFID (13.56 MHz)High Frequency – contactless payment, transit cards, library systems.UHF RFID (860–960 MHz)Ultra-High Frequency – retail inventory, supply chain, long-range tracking.NFCNear Field Communication – the smartphone-readable subset of HF RFID.Microwave RFID (2.45 GHz)Microwave – RTLS, toll collection, active and semi-passive tags.

Key concepts

Tag URI & Pure Identity URIThe two URI forms that represent what is on a tag and what it means.Filter ValueThe 3-bit field that indicates packaging level without changing identity.Partition ValueHow bits are split between company prefix and reference field.GS1 Company PrefixThe number that identifies who owns a barcode or EPC.GTINThe Global Trade Item Number - the barcode number behind every product.Application Identifiers (AIs)The prefix codes that define what data follows in a GS1 barcode. 59 AIs documented.

Barcode fundamentals

The vocabulary every barcode page on this site shares - modules, guards, parity, check digits. Start here if any of the construction tabs lose you.

ModuleThe smallest dark or light unit - the building block every other measurement is built on.X-dimensionThe physical width of one module, in mils or millimetres. Determines how big the printed barcode is.Quiet zoneThe blank margin around a barcode. Forget it and the symbol won't scan, even if every bar is perfect.Bar and spaceThe two visible elements of every 1D linear barcode - a bar is a run of dark modules, a space is a run of light.Check digitA redundant digit that catches scan and transcription errors. GS1 mod-10, Code 39 mod-43, Code 128 mod-103.Wide and narrow elementsThe two-width construction used by Code 39, Codabar, and the 2-of-5 family. Every bar and space is either narrow or wide.Wide-to-narrow ratioThe ratio of wide-element to narrow-element width in two-width symbologies (Code 39, Codabar, I2of5). Default 1:3.Start and stop charactersThe sentinels that bracket a 1D barcode - visible * in Code 39, A/B/C/D in Codabar, silent Start codes in Code 128.SymbologyThe full specification of how a barcode encodes data. EAN-13, Code 128, QR Code - these are symbologies.Character setWhat characters can be encoded. Digits-only, 43-char alphanumeric, full ASCII, byte mode, Kanji.Guard patternFixed bar patterns that bracket EAN/UPC symbols and let scanners self-calibrate.L-codes, G-codes, R-codesThe three different 7-module patterns EAN/UPC uses to encode digits 0-9.Parity selectionHow EAN-13 carries an implicit 13th digit via the L-vs-G choice on each left-half digit.Number system digitThe leading UPC-A digit that says retail vs variable-weight vs pharma vs coupon.

Messaging protocols

MQTTLightweight pub/sub messaging for IoT and RFID event streaming.AMQPEnterprise message queuing for RFID middleware and supply chain.HTTP/RESTRequest/response APIs and webhooks for reader management.WebSocketsFull-duplex bidirectional streams for real-time RFID dashboards.CoAPConstrained Application Protocol - lightweight REST over UDP for IoT.LLRPLow Level Reader Protocol - GS1 standard for UHF reader control.OPC UAIndustrial automation protocol for RFID in manufacturing and Industry 4.0.EPCISGS1 standard for sharing RFID supply chain visibility events.

Brokers & servers

MosquittoLightweight open-source MQTT broker for edge and IoT deployments.HiveMQEnterprise MQTT platform with clustering and horizontal scaling.AWS IoT CoreManaged cloud MQTT broker with rules engine and device shadows.RabbitMQOpen-source multi-protocol message broker for RFID middleware.Apache QpidApache AMQP 1.0 broker, library, and message router.NginxHigh-performance reverse proxy and API gateway for RFID services.Apache HTTPDThe original open-source HTTP server for hosting RFID web apps.API GatewaysManaged services for securing and routing RFID API traffic.

Printer languages

ZPLZebra Programming Language – the command language for Zebra label printers.SBPLSATO Barcode Printer Language – the command language for SATO printers.TSPLTSC Printer Language – the command language for TSC Auto ID printers.DPLDatamax Programming Language – the command language for Honeywell/Datamax printers.

Barcode symbologies

EAN-131D

International Article Number (13-digit)

The most widely used retail barcode in the world. EAN-13 encodes a 13-digit GTIN and appears on virtually every product ...

UPC-A1D

Universal Product Code (12-digit)

The standard retail barcode in the United States and Canada. UPC-A encodes a 12-digit GTIN-12, which is a subset of GTIN...

EAN-81D

International Article Number (8-digit)

A compact version of EAN-13 designed for small packages where a full-size barcode would not fit - chewing gum, lipstick,...

ITF-141D

Interleaved Two of Five (14-digit)

A barcode printed directly on corrugated cardboard outer cases. ITF-14 encodes a 14-digit GTIN-14, which is the full-len...

GS1-1281D

GS1-128 (formerly UCC/EAN-128)

The workhorse barcode of logistics. GS1-128 uses Application Identifiers (AIs) to encode multiple data elements in a sin...

GS1 DataMatrix2D

GS1 DataMatrix (2D)

A 2D barcode that encodes the same Application Identifier data as GS1-128 but in a much smaller space. GS1 DataMatrix is...

GS1 DataBar1D

GS1 DataBar (formerly RSS)

A family of compact barcodes designed for items too small for traditional barcodes or that need additional data at point...

QR Code2D

QR Code / GS1 Digital Link

When combined with GS1 Digital Link, a QR code becomes both a scannable barcode and a web link. The URL embeds the GTIN,...

Micro QR2D

Micro QR Code (ISO/IEC 18004 Annex 1)

The compact QR Code variant defined in Annex 1 of ISO/IEC 18004. Four sizes (M1 to M4, 11×11 through 17×17 modules) with...

MicroPDF4172D

MicroPDF417 (ISO/IEC 24728)

The compact variant of PDF417, defined in ISO/IEC 24728. Reuses PDF417's 929-codeword alphabet, three compaction modes (...

Encoding schemes

SGTIN-960x30

Serialized Global Trade Item Number (96-bit)

96 bits

Encodes a GS1 GTIN (barcode number) plus a serial number into 96 bits. This is the most common EPC scheme - it is the o...

SGTIN-1980x36

Serialized Global Trade Item Number (198-bit)

198 bits

Same as SGTIN-96 but with a 140-bit serial number field that supports alphanumeric serials (6-bit encoded). Used when th...

SSCC-960x31

Serial Shipping Container Code (96-bit)

96 bits

Encodes an SSCC - the 18-digit number on shipping labels that identifies a unique logistics unit (a pallet, a case, a p...

SGLN-960x32

Serialized Global Location Number (96-bit)

96 bits

Encodes a GLN (Global Location Number) with an extension to identify a specific sub-location. GLNs identify physical loc...

SGLN-1950x39

Serialized Global Location Number (195-bit)

195 bits

Same as SGLN-96 but with a 140-bit extension field supporting alphanumeric values (6-bit encoded). Used when the extensi...

GRAI-960x33

Global Returnable Asset Identifier (96-bit)

96 bits

Identifies a returnable asset - reusable containers, pallets, kegs, crates, trolleys, and rail cars. The GRAI includes ...

GRAI-1700x37

Global Returnable Asset Identifier (170-bit)

170 bits

Same as GRAI-96 but with a 112-bit serial field supporting alphanumeric serials (6-bit encoded).

GIAI-960x34

Global Individual Asset Identifier (96-bit)

96 bits

Identifies an individual asset that is not returnable - IT equipment, tools, vehicles, machinery. Unlike GRAI there is ...

GIAI-2020x38

Global Individual Asset Identifier (202-bit)

202 bits

Same as GIAI-96 but with a 150-bit asset reference field supporting alphanumeric values (6-bit encoded).

GID-960x35

General Identifier (96-bit)

96 bits

A general-purpose EPC scheme not tied to GS1 keys. Uses an EPCglobal General Manager Number instead of a GS1 Company Pre...

GDTI-960x2C

Global Document Type Identifier (96-bit)

96 bits

Identifies a document - a certificate, a permit, a ticket, a licence, a tax receipt. The GDTI encodes a document type a...

GDTI-1740x3E

Global Document Type Identifier (174-bit)

174 bits

Same as GDTI-96 but with a 119-bit serial field supporting alphanumeric document serials (6-bit encoded).

GSRN-960x2D

Global Service Relation Number (96-bit)

96 bits

Identifies a relationship between a service provider and a recipient - a loyalty card member, a hospital patient, a lib...

GSRNP-960x2E

Global Service Relation Number - Provider (96-bit)

96 bits

Identifies a service relationship from the provider side. While GSRN identifies the recipient (the patient, the member),...

CPI-960x3C

Component/Part Identifier (96-bit)

96 bits

Identifies a component or part using a company prefix and a component/part reference. Used in manufacturing to track ind...

CPI-var0x3D

Component/Part Identifier (variable length)

96 bits

Variable-length CPI encoding with a 6-bit encoded alphanumeric component part reference (null-terminated) followed by a ...

SGCN-960x3F

Serialized Global Coupon Number (96-bit)

96 bits

Encodes a GS1 Global Coupon Number with a serial component, enabling unique identification of individual coupons for red...

ITIP-960x40

Individual Trade Item Piece (96-bit)

96 bits

Identifies an individual piece of a trade item that is naturally sold in sets - the left shoe of a pair, one lens of a ...

ITIP-1100x41

Individual Trade Item Piece (110-bit)

110 bits

Same as ITIP-96 but with a longer 38-bit serial number field (matching SGTIN-96 serial capacity).

ADI-var0x3B

Aerospace and Defence Identifier (variable length)

96 bits

US Department of Defence and aerospace identifier. Uses a CAGE code (Commercial and Government Entity) or DoDAAC (DoD Ac...