GS1 and RFID: The Role of GS1 Standards

Who is GS1?

GS1 is a global, not-for-profit organisation that develops and maintains standards for identifying products, locations, shipments and assets, and for sharing data about them. If you have ever seen a barcode scanned at a supermarket checkout, you have seen a GS1 standard at work: the number under that barcode is a GTIN (Global Trade Item Number), and the company part of it was licensed to the brand owner by a GS1 organisation.

GS1 works through a global office and a network of national member organisations in well over a hundred countries. Each member organisation licenses company prefixes to businesses in its country, provides training and helps local industry apply the standards. In India this role is played by GS1 India, the national GS1 member organisation, set up under the aegis of the Ministry of Commerce and Industry together with leading industry bodies. Indian brands that print retail barcodes typically get their company prefix through GS1 India.

Why does this matter for RFID? Because a UHF RFID tag is, in most supply-chain uses, just a radio-readable carrier for the same kind of GS1 identifier a barcode carries. GS1 standards decide how that identifier is structured, how it is packed into tag memory, how readers talk to the tag, and how the resulting scan data is shared between companies.

From EPCglobal to GS1: one family of standards

In the early 2000s, research work on the "Electronic Product Code" (EPC) and low-cost UHF tags led to the creation of EPCglobal, an organisation set up within the GS1 system to commercialise and standardise EPC-based RFID. Over time the EPCglobal standards were fully absorbed into GS1, and today they are simply GS1 standards. You will still see the "EPC" name everywhere, but the owner and maintainer is GS1.

The main pieces of this family are:

• UHF Gen2 air interface - the protocol a UHF reader and a passive tag use to communicate (inventory rounds, singulation, read, write, lock, kill). It is commonly called "EPC Gen2" or "Gen2", and it is aligned with the international standard ISO/IEC 18000-63. Later versions (often called Gen2v2) added optional security and privacy features such as cryptographic authentication and the ability to hide or untrace parts of memory.
• EPC Tag Data Standard (TDS) - defines how GS1 keys are turned into EPCs: the pure-identity URI form, the tag URI form, and the exact binary layouts (SGTIN-96, SSCC-96 and so on) written into the tag's EPC memory bank.
• Tag Data Translation (TDT) - a machine-readable companion to TDS that lets software automatically convert between binary, hex, URI and GS1 element-string formats, so developers do not have to hand-code every scheme.
• EPCIS and CBV - standards for capturing and sharing what happened to tagged objects, described in more detail below.

For a wider view of RFID standards, including HF and LF, see RFID Standards.

The barcode-to-RFID link: GTIN to SGTIN

A GTIN identifies a product type: every 500 ml bottle of a particular shampoo carries the same GTIN, and every medium blue T-shirt of a particular style carries the same GTIN. That is fine for checkout, where the till only needs to know the price, but it cannot tell one bottle or one shirt from another.

RFID's big advantage is that every tag can be unique. GS1 achieves this with the SGTIN (Serialised GTIN): the GTIN plus a serial number. The GTIN tells you what the item is; the serial tells you which one. Two shirts of the same style and size share a GTIN but have different SGTINs.

Because SGTIN is derived from the GTIN, a brand that already barcodes its products has done much of the groundwork for RFID. The product master data, the company prefix and the item references are all reused. What is new is the serial number management: someone must make sure no serial is ever issued twice for the same GTIN.

GS1 identification keys used in RFID

SGTIN is the most common EPC scheme, but GS1 defines several other keys, each designed for a particular kind of object. Choosing the right one matters, because trading partners and software interpret the tag based on its scheme.

The "-96" schemes fit in the 96-bit EPC memory that almost every UHF chip supports, and they use numeric serials. The longer schemes (such as SGTIN-198 or GIAI-202) allow alphanumeric serials but need chips with larger EPC memory. For most retail item tagging, SGTIN-96 is the default choice.

Getting a GS1 company prefix - and why random EPCs are a problem

Every GS1 key starts with a GS1 company prefix licensed to your organisation. That prefix is what guarantees global uniqueness: no other company in the world can legitimately issue identifiers starting with your prefix. In India, the prefix is obtained through GS1 India, and the same prefix covers your barcodes and your RFID EPCs. If you do not yet have one, our barcode registration service can guide you through the application and the choice of prefix capacity.

Why not just write any number on the tag?

Technically, a Gen2 tag will accept any bit pattern you write to its EPC bank. Many closed-loop systems - a library, a laundry, a factory's own tool crib - work fine with made-up numbers because nobody outside will ever read them. The trouble starts when tagged goods leave your four walls:

• Collisions: if two suppliers both start their serials at 1 with no prefix, a retailer's system will see two different shirts as the same item.
• Misinterpretation: a random EPC whose first byte happens to be 0x30 looks like an SGTIN-96 to every decoder and may decode to a GTIN that belongs to somebody else.
• Rejection: retailers and brands with RFID programmes usually specify GS1 EPC encoding in their supplier requirements, and non-compliant tags can lead to rework or chargebacks.
• Lost data value: without a GS1 structure, nobody downstream can link the tag to your product master data.

Encoding rules recap and filter values

The EPC Tag Data Standard packs a GS1 key into a fixed binary layout. For SGTIN-96 the fields are, in order: an 8-bit header (0x30, which is why SGTIN-96 EPCs in hex start with "30"), a 3-bit filter value, a 3-bit partition value, the company prefix and item reference (together 44 bits, split according to the partition), and a 38-bit serial number. The partition value tells a decoder how many digits belong to the company prefix, which is why the length of your prefix matters when encoding.

A few practical rules apply to SGTIN-96:

• The serial must be a whole number that fits in 38 bits (typically up to about 274 billion) and must not have leading zeros.
• The GTIN check digit and the leading indicator digit placement follow fixed rules - use tested software or a library based on TDT rather than writing your own bit-packing from scratch.
• Always verify by decoding the written EPC back to a GTIN and serial before production runs.

Filter values

The 3-bit filter value is a hint about what kind of object the tag is on, so that readers can quickly select only the tags they care about. A dock-door reader might read only cases and pallets, while a store reader focuses on point-of-sale items. For SGTIN, commonly used filter values include 1 for a point-of-sale trade item, 2 for a full case for transport, 4 for an inner pack, 6 for a unit load, and 0 for "all others". Filter values do not change the identity of the item; they just make reading more efficient.

For the full bit-by-bit worked example, memory banks, locking and passwords, read EPC Encoding & Tag Memory.

EPCIS, CBV and GS1 Digital Link

EPCIS: sharing what happened

Reading a tag is only useful if the read becomes business information. EPCIS (Electronic Product Code Information Services) is the GS1 standard for recording and sharing visibility events. Each event answers four questions:

• What - which objects (EPCs, or GTIN plus batch quantities) were involved
• Where - the read point and business location, usually expressed as SGLNs
• When - the date, time and time zone of the event
• Why - the business step (such as shipping or receiving) and the disposition (such as in transit or sellable)

EPCIS defines event types for simple observations, for packing items into a case (aggregation), for transformations (raw material into finished goods) and for linking objects to business transactions such as a purchase order. Recent versions also support JSON-based exchange and web APIs, making it easier to integrate with modern software. EPCIS works equally well with barcode scans; it is not limited to RFID.

CBV: a common vocabulary

The Core Business Vocabulary (CBV) is EPCIS's companion standard. It defines standard values for the "why" - business steps like shipping, receiving and packing, and dispositions like in_transit or sellable_accessible. Without CBV, one company might record "despatched" and another "shipped", and the data would not line up. How EPCIS fits into middleware and ERP is covered in RFID Software Integration.

GS1 Digital Link in brief

GS1 Digital Link is a way of expressing GS1 keys as web addresses (URIs), so that a single identifier can be both a supply-chain key and a link to online information. It is most visible in 2D barcodes such as QR codes on packaging, but it also connects to RFID and NFC: an NFC tag can carry a Digital Link URI that a phone opens, and recent versions of the Tag Data Standard include ways to align EPCs with Digital Link. For now, most UHF supply-chain tags still use the classic binary schemes described above.

GS1 RFID work in retail, healthcare and logistics

GS1 and its member organisations run industry working groups that turn the general standards into sector guidelines:

• Apparel and general retail: the most mature RFID sector. Guidelines cover item-level SGTIN encoding, tag placement, inspection and read-quality expectations, and how suppliers and retailers share data. Large retail programmes generally build their supplier requirements on GS1 EPC encoding.
• Healthcare: GS1 healthcare work covers identification of medicines and medical devices, patient identification (GSRN on wristbands), and asset tracking of equipment using GIAI. RFID is used selectively here, often alongside 2D barcodes.
• Transport and logistics: SSCC for shipments, GRAI for returnable transport items such as pallets and crates, and SGLN for locations. EPCIS is used to share shipping and receiving events between partners.

In India, the same principles apply to domestic retail chains, exporters supplying global brands, and importers receiving tagged goods. Importers should check that their systems can decode incoming EPCs correctly - see RFID for Importers: Step by Step.

GS1 and the RAIN RFID Alliance: different roles

People often confuse these two. GS1 is the standards body: it writes and maintains Gen2, TDS, EPCIS, CBV and the identification keys, and it licenses company prefixes. The RAIN RFID Alliance is an industry association of companies in the UHF RFID ecosystem - chip makers, inlay makers, reader makers, integrators and end users. Its job is to promote awareness and adoption of passive UHF RFID based on the Gen2 / ISO/IEC 18000-63 protocol, under the "RAIN" brand name. In short: GS1 defines the rules and the identifiers; RAIN promotes the technology and the market. The two are complementary, and a typical retail RFID project uses GS1 identifiers on RAIN (UHF Gen2) tags.

Whatever standards you follow, the radio side must also obey local regulations. In India, passive UHF RFID operates in the 865-867 MHz band, with readers limited to 4 W EIRP (1 W transmitter power), and equipment should be type-approved for India.

Practical checklist for a brand starting RFID with GS1 identifiers

1. Confirm your GS1 company prefix and its capacity. If you do not have one, apply through GS1 India before ordering encoded tags.
2. Clean up product master data - every SKU should have a correct GTIN, description, size and colour in your ERP.
3. Pick the right key for each object: SGTIN for products, SSCC for shipments, GRAI for returnables, GIAI for your own assets.
4. Read your buyers' RFID requirements - many specify encoding scheme, filter value, chip or inlay performance, and tag placement.
5. Design a serial number policy: who issues serials, how duplicates are prevented, and how printers and encoding stations stay in sync.
6. Choose tags and chips suited to the product and the buyer's approved list - see UHF RFID labels.
7. Set up encoding and verification on RFID printers or encoders, with a decode-back check and void handling for failed tags.
8. Record TID with EPC at encoding time for traceability and anti-counterfeit checks.
9. Plan data sharing - advance shipping notices with EPC lists, and EPCIS events if partners use them.
10. Pilot, measure read rates, then scale.

If you want expert help with prefix planning, encoding rules and buyer compliance, our RFID consulting team works with Indian brands and exporters every day. For structured, hands-on training on GS1 encoding and the rest of the RFID stack, see our RFID courses in India.