Do I need an M2M SIM?
M2M SIM stands for Machine-to-Machine Subscriber Identity Module which is a SIM card specially designed for Internet of Things (IoT) applications, often also referred to as an IoT SIM.
An M2M SIM connects a device to the cellular network in much the same way as the SIM in your mobile phone. M2M SIMs are usually only programmed to send and receive data, so they don’t support voice calls. Some may support SMS which can be important if SMS is needed to configure your device or used as a wake-up function for devices that send data infrequently.