TID FAQs

Verified Impinj chips: what "genuinely unique" actually means in practice

GCN's APP independently decodes the TID directly from the physical chip on every tag batch.

GCN confirms that every unit carries a distinct, factory-assigned TID with no duplicates, and that the chip itself is genuine Impinj RAIN RFID silicon (Impinj M830). GCN independently decode from the raw chip data captured directly off the reader, by checking the chip's own header bytes against Impinj's published chip architecture.

Impinj chips operate on the EPC Gen2v2 UHF standard (ISO/IEC 18000-63), the global RAIN RFID standard maintained by the RAIN RFID Alliance, which governs how RFID readers and tags from any compliant manufacturer communicate. You can read more about how this standard works on Impinj's own RFID standards page.

What is a TID, and why does it matter?

Every RFID chip has two different numbers on it, not just one.

The first number (the EPC) is the one that identifies your specific product — this is what gets assigned when a tag is added to your Digital Product Passport, and it's what most people think of as "the tag's number."

The second number (the TID) is different — it's burned into the chip itself by the manufacturer when it's made, and it can never be changed or rewritten by anyone, including GCN. Think of it like a chip's own permanent serial number, separate from whatever product identity gets assigned to it later.

Why having both matters

On its own, an EPC can, in principle, be copied onto another blank tag — creating a counterfeit that looks genuine when scanned. This is a limitation of RFID technology generally, not specific to any one platform.

Where a chip has a genuinely unique TID, GCN's platform can check both numbers together every time a tag is scanned. If someone tried to copy a product's EPC onto a different physical chip, the TID wouldn't match what's on record — and the copy would be detected. This is a real, physical layer of security that a printed QR code simply cannot offer, since a QR code has no equivalent hidden, unchangeable identity.

Not all tags offer this

Here's the honest, important part: not every RFID tag on the market actually provides a genuinely unique TID, even though the TID field technically exists on every chip. Cheaper or lower-quality tags sometimes ship with identical TIDs across many units — meaning the field is present, but doesn't actually tell one tag apart from another. This isn't something you can tell just by looking at a tag; it depends on the specific chip and manufacturer.

This is exactly why GCN independently tests every tag supplier's chips before recommending them, rather than trusting a spec sheet alone.

What this means for your choice of tags

Tags with verified, genuinely unique TIDs typically cost a little more than tags without this guarantee. Depending on your products and how important this extra layer of security is to you, you may choose:

Tags with verified unique TIDs, for higher-value products or where counterfeit protection matters most
Simpler tags without this feature, for lower-value products where the cost saving matters more

When you receive your DPP Package, we'll provide the specific TID information relevant to the exact tags you've chosen and purchased — so you'll always know exactly what level of protection your specific tags provide, rather than a generic claim that may not apply to your particular batch.

Questions about which tag option is right for your products? Contact GCN to discuss.

Report abuse