Here’s a decent summary (from a good antenna vendor):
Generally, you can take advantage of modular approval from the module vendor (uBlox) if:
- no other radios apart from cellular in the product
- not used within 20cm of a human body (so you can skip SAR)
- lower gain antenna than the one the approvals were done with
…you’ll still have to do FCC 15b for unintentional radiator, but you can do this with the radio part turned off.
Then, there’s PTCRB, which is GSM approvals - ie approval for your device to be connected to a GSM/3GPP spec network:
- The uBlox module has PTCRB approval, but…
- If your device has the antenna inside it, or has a cabled antenna which is <20cm from the device, you need to do PTCRB OTA testing. This is kinda expensive - usually $50k+ - as it requires certified labs and a lot of equipment (TRP/TIS etc) and time.
- It’s sometimes possible for someone who integrates a module (eg Particle) to do some of the required testing. They would have to convince PTCRB the device met the prerequisites and so on. If you have done this, you generally claim it fairly loudly (see: other cellular module integrators).
Finally, there’s carrier approval:
- This can be somewhat arbitrary. Particle being an MVNO may help here, but they may have to run stuff past their host carrier.
- Technically it’s approval of the way an app works over the cellular network, as well as minimum performance levels.
- I’m sure it’s quite different for M2M devices than it was when I was making iPhones (when there were literally hundreds of user interface tests)