Multi-SIM devices
This refers to devices that are designed to house two or more physical SIM cards. For IoT applications, multi-SIM solutions are most often used in devices such as fleet trackers and industrial equipment. Usually, one SIM card connects the device to your core mobile network, while another card connects to your back-up provider. This can help ensure ongoing connectivity in case of a signal outage with your core provider.
Multiple networks on a single SIM
A multi-network SIM is similar to a single network SIM in that it is procured from a primary operator, but the profile is built to allow access to multiple networks per country. In most key markets this means there is choice between 2, 3 or sometimes 4 or 5 networks per country.
Multiple profiles on a single SIM
A SIM profile comprises all the information required for a device to connect to a mobile network operator, including the file system, operator access keys and International Mobile Subscriber Identity (IMSI). A standard SIM card usually only has enough memory capacity for one profile. In other words, you get one connectivity option per-SIM.
Only a minority of devices are able to house and support more than one SIMs. IoT deployments are typically bound by cost, size and energy efficiency so keeping component count and size down is often essential. So for businesses that need a multi-SIM solution, instead of having multiple physical cards in a device, the best option usually involves a single SIM that can support multiple profiles although a multi-network SIM is a good compromise.
One way of doing this is with a SIM card that incorporates a type of technology known as eUICC (Embedded Universal Integrated Circuit Card). With this, a single SIM card can host several profiles at once. You can also add, remove and manage these profiles remotely.