The SIM card requirements are:
- PIN code is disabled.
- Micro-SIM size.
- GPRS (GSM, 2G) data plan. 3G, 4G or LTE speeds are not needed as bttn has a 2G GSM/GPRS radio.
- Phone number.
- Ability to receive SMS.
- Phone book for storing contacts*
The Button Corporation can provide globally roaming M2M SIM cards for business customers. Please contact email@example.com for more information.
* bttns running firmware 201503 or 201506 store APN settings on the SIM card's phone book. Some SIM cards have a maximum character limit of 8 or 20. This limits the possibility of using very long APN names. 20 character limit is the most common. The APN string is stored on the phone book as follows (example): APN:internet (12 characters). Look for an operator that has a short GPRS APN name.
bttns running firmware 201603 or later store the APN settings on the bttn's onboard flash memory, so with this firmware version the SIM phone book is no longer needed and all APN addresses will fit.