Devices: modules, GPS trackers and routers

Model-by-model setup guides: where the APN goes, which radio technologies the device uses, and the settings that stop a roaming IoT SIM from connecting. Every command and menu path cites the maker’s documentation, with the date we checked it.

Three things decide whether a device works with an IoT SIM:

1. The APN, set by AT command (modules), in the web interface (routers) or by SMS (trackers).
2. Roaming accepted: a multi-network SIM often registers in roaming (+CEREG: 0,5); devices or firmware that refuse roaming stay offline.
3. The radio technology: 2G-only devices stop where operators switch 2G off. See the 2G and 3G shutdown dates.

• Cellular IoT modules: APN and network setup, model by model
  APN, radio technology and registration commands for LTE-M, NB-IoT, LTE Cat-1, Cat-4 and 5G modules from the main makers, each citing the maker's AT manual.
• 4G and 5G routers: IoT SIM setup, model by model
  Where to set the APN of an IoT SIM in cellular routers and gateways, which options block roaming SIMs, and how to reach the router without a public IP.
• GPS trackers: IoT SIM setup by SMS, model by model
  SMS commands to set the APN and server of GPS trackers with an IoT SIM, parameter by parameter, and which models still depend on 2G networks.