How to enable TT feature in NTAG213 TT chips

NTAG213 TT is a special NFC Chip that can detect wheter it has been tampered and return a different message. This function is called TT (Tag Tamper) feature and in general it is used for marketing purposes. Most important, NTAG213 TT is compatible with all Android NFC-enabled devices and all iPhones from 7 onwards.

How NTAG213 TT works

The operation is very simple: these chips have an elongated antenna filament, so that the chip is aware if the filament is intact or broken. Adding a TT message to this chip means adding a suffix (?t=00000000) to the URL you encoded. When the antenna filament is broken, this suffix changes.

Before starting: what you need

Basically, you need 3 things:

  • Some NTAG213 TT stickers, of course.
  • TagXplorer, a free software available for Windows, MacOS and Linux. This software is developed by NXP, which is also chip manufacturer.
  • A compatible NFC Reader/Writer, such as the uTrust 3700F. There are other readers compatible with TagXplorer, but we personally tested this one, and we guaranteee it. Also, this reader is compatible with Windows, MacOS and Linux. However, this tutorial would be very similar with any other reader.

So, if you already have these 3 things, you have to install reader's driver for your OS, plug the reader in a USB port, and launch TagXplorer. Here we go!

1. Connect Reader and Tag

Select the uTrust 3700F reader from the drop-down menu (1), then click on "Connect Reader" (2). Place the Tag on the reader and click "Connect Tag" (3).

Encoding NTAG213 TT with TagXplorer

2. Encode the main URL

First, you need to encode the link where the Tag should point (until it has been broken). Click on "NTAG Operations" (4), then on "Mirroring Features" (5), then on "NTAG213 Tag Tamper" (6). In "Data" field (7), write the URL to be programmed, then tick "Add NTag213TT Message" (8): in this way, the suffix "?t=00000000" will be added to the URL previously entered, then click on "Write To Tag" (9) to actually encode the Tag.

Encoding NTAG213 TT with TagXplorer

3. Add the Tag Tamper message

Now you have to insert the actual TT message, that is the different suffix to be shown when the Tag is broken. Click on "NTAG213 TT" (10), go to "NFC Counter, TT Status and Message" tab (11). In the "TT Message" field (12), enter your TT message. Generally, the string "FFFFFFFF" is used, but it can be customized: the only limit is that it must be a 4-byte message. Then click on "Write TT Message" (13) to encode the TT message on the Tag.

Encoding NTAG213 TT with TagXplorer

4. Activate the TT function

Final phase: the activation of the Tag Tamper function. Without activation, the message does not change when the Tag is broken.

Switch to the "User configuration" tab (14), then enable the TT function by clicking on "Enable TT Feature" (15). From the "TT Lock" drop-down menu (16), you can choose whether to permanently lock the TT message (entered in step 12) or to leave it rewritable. Finally, click on "Write Config" (17): the NTAG213 TT Tag is ready.

Encoding NTAG213 TT with TagXplorer

Please note

The TT message can also be encoded with NFC TagWriter application for Android.