A few of the customers have reported NFC connectivity issues when using some devices which makes the burning process a little troublesome. This behavior with the link breaking can certainly occur with NFC, it's just the nature of the technology with such a short-range wireless communication. This is especially true at relatively higher bit rates where packets can get lost or corrupted easier (i.e. during the burn process). NFC was chosen as a method to control the programmable tokens because NFC equipment is relatively cheap, easy to find and consumes less power compared to others (BLE, Wifi etc.). But the protocol (or to be entirely correct, a set of protocols) NFC is based on, was originally meant to be used primarily in contactless payment systems (or similar), where a powered device (i.e. a payment terminal) and a powerless card (i.e. a credit card or a transport card) are communicating with each other for very short amount of time. The concept of data exchange is obviously different with NFC programmable tokens. On top of that the NFC antenna used in our products even thinner and more miniature than, for instance, NFC tags to allow keeping the dimensions of the tokens as small as possible. Another inconvenience that plagues the burning process is that with the wide variety of Android phones comes many different locations for the NFC chip — and thereby some frustrating experiences when users don't find it. On one device it might be located at the top, another in the center, and another at the bottom.
Here is something to keep in mind when using our NFC burner apps:
1) It's important that the NFC area on the token is touching the NFC area on the writer device (NFC module or the phone/tablet's NFC chip) when programming the token. Check the manufacturer's website to find the exact location of the NFC module, as this may vary significantly. See the example below showing NFC detection areas of a few Samsung phones. A full list is available here.
2) Turn off and on the token and try again by removing and placing the device back onto the NFC area
3) Verify if the NFC link is successfully established. Android devices produce specific sounds (depending on the model etc.) during establishing NFC links, these sounds are different for successful and unsuccessful attempts.
With USB NFC modules, the established NFC links are indicated by a green LED indicator. With ACR122, for example, a successfully established link is indicated by a green led flashing once and then turning off after a couple of seconds; while with unsuccessful links the led is turning red.