Reference

EPC & Barcode Glossary

Every EPC encoding scheme, barcode symbology, and GS1 Application Identifier used in RFID and automatic identification. Each page explains structure, field layouts, and how barcodes and RFID tags carry the same identifiers.

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

Aztec Code2D

Aztec Code (ISO/IEC 24778)

A square 2D matrix symbology built around a central bullseye finder pattern. Unlike QR Code and Data Matrix, Aztec Code ...

Codabar1D

Codabar (ISO/IEC 16388)

A self-checking linear barcode whose payload supports digits plus - $ : / . +. Each symbol is bracketed by one of the st...

CODABLOCK-F2D

CODABLOCK-F stacked symbology

A stacked barcode that arranges multiple Code 128-style rows into a rectangular symbol. Row indicators and checks allow ...

Code 111D

Code 11 linear barcode

A compact variable-width linear symbology designed for numeric strings and hyphens. It normally uses one or two weighted...

Code 1281D

Code 128 (ISO/IEC 15417)

A dense linear barcode with three code sets. Code Set C packs pairs of digits efficiently, while Sets A and B cover cont...

Code 391D

Code 39 (ISO/IEC 16388)

A widely deployed alphanumeric linear barcode. Every character contains nine elements, three of which are wide, and the ...

Data Matrix2D

Data Matrix ECC 200 (ISO/IEC 16022)

A compact square or rectangular matrix barcode identified by its solid L-shaped finder pattern and alternating timing bo...

Interleaved 2 of 51D

Interleaved 2 of 5 (ISO/IEC 16390)

A numeric linear barcode that interleaves pairs of digits: one digit is encoded by the bars and the other by the spaces....

Industrial 2 of 51D

Industrial 2 of 5 linear barcode

An older non-interleaved member of the 2-of-5 family. Each digit is encoded in the bars while the intervening spaces car...

Intelligent Mail1D

USPS Intelligent Mail barcode

The United States Postal Service four-state barcode that combines routing and tracking information in one symbol. Each b...

LOGMARS1D

Logistics Applications of Automated Marking and Reading Symbols

The United States Department of Defense application of Code 39. LOGMARS standardises print quality and requires the modu...

MaxiCode2D

MaxiCode (ISO/IEC 16023)

A fixed-size matrix barcode with hexagonal modules arranged around a central bullseye. It was designed for fast reading ...

PDF4172D

PDF417 (ISO/IEC 15438)

A stacked 2D barcode whose rows contain PDF417 codewords. Text, byte, and numeric compaction modes support large payload...

PLANET Code1D

Postal Alpha Numeric Encoding Technique

A legacy USPS two-state height-modulated barcode used to track letter mail. USPS retired PLANET Code in favour of the In...

TLC392D

TCIF Linked Code 39

A composite symbology that links a Code 39 primary symbol to a MicroPDF417 secondary component. The linkage flag tells a...

UPC-E1D

Universal Product Code, zero-suppressed

A compressed form of UPC-A for small retail packages. UPC-E suppresses predictable zeroes from eligible UPC-A manufactur...

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...