Most of us are already familiar with the concept of SIM cards, which we all use on our mobile phones, tablets, and other mobile devices.
SIM stands for Subscriber Identity Module, and as the name suggests, allows network providers to identify their subscribers, the plans they’re subscribed to, and provide connectivity.
In IoT deployments that utilize cellular connectivity, SIM cards are also used to enable connectivity between IoT devices and from one IoT device to the network. However, a standard SIM card we have on our phones isn’t really adequate for IoT deployments, and this is where the M2M SIM card comes in.
What Is an M2M SIM Card?
M2M stands for ‘Machine-to-Machine’, referring to how the M2M SIM card is designed to provide connectivity between two or more end devices. For instance, communication between an IoT sensor with a computer can be considered as an M2M communication.
An M2M SIM card performs almost the same way as a standard SIM card but has some unique features and functions that aren’t available in traditional SIM cards.
Below, we will discuss these key differences.
M2M SIM Cards VS Standard SIM Cards
As discussed, standard SIMs and M2M SIM cards are designed for very different purposes. The standard SIM cards in our phones are designed for general communication, for transferring data (i.e. voice data, text data) between a mobile terminal (i.e. smartphone) to a cellular tower, and the other way around.
An M2M SIM, on the other hand, is designed so that two devices (or machines) can communicate directly with each other, often across large distances.
One of the key benefits of using M2M SIM cards is a centralized management software where we can control all the different devices using the M2M SIM cards from a single system.
As we know, IoT systems can involve a lot of interconnected IoT devices, and there are even IoT deployments that involve hundreds if not thousands of devices. With that being said, it can be difficult to monitor and control all of these devices if you are using a traditional SIM card.
IoT data plans tailored for M2M SIM cards will provide a device management software where you can monitor data usage and SIM activity for each IoT device in real-time.
This function also allows data aggregation, which is another important feature provided by M2M SIM cards and IoT data plan, as we will discuss below.
An IoT deployment can involve a lot of different interconnected devices, and each of them might consume a different amount of data in any given period. There will be cases where one device will overuse data, and another will underuse, and this is where data aggregation comes in.
In a data plan designed for IoT like Truphone for Things, the data usages between different devices will be aggregated to ensure cost-efficiency, which can be extremely important in large-scale IoT projects.
Remote SIM Provisioning
For M2M SIM cards with eSIM form factor (more on this later), there is another important feature called Remote SIM Provisioning (RSP). RSP basically allows us to move between different networks without replacing the physical SIM card, which is useful if you plan to expand your IoT deployment to different locations or countries, and also for mobile IoT applications like autonomous vehicles.
M2M SIM cards are designed to be much more durable and robust than a standard SIM card.
Our standard SIM cards in our phones are designed only for a couple of years of normal usage before we’ll need to replace them and are not designed to withstand harsh environments like extreme temperatures.
As we know, many IoT devices are deployed in remote locations, for example in the depth of the ocean with extreme water pressure and low temperature. An M2M SIM card can be an answer to this issue, typically with a tolerance range between -40°C and 105°C. M2M SIM cards are also corrosion-resistant and are designed to last for up to a decade.
M2M SIM Card VS eSIM
The terms M2M SIM and eSIM are often used interchangeably with each other, and while there are indeed some connections between the two, especially in IoT implementations, they are not exactly the same.
eSIM is a form factor of the SIM, and there are actually eSIMs designed not for M2M/IoT usage. For example, Apple Watch and the latest iPhones are using eSIM.
To really understand the concept of eSIM, we have to discuss that SIMs (including M2M SIM cards) can come in various different form factors:
- 1FF (full SIM), 85.6mm × 53.98mm × 0.76 mm: roughly the same size as your credit card. Not commonly used in consumer devices.
- 2FF (Mini-SIM), 25mm x 15mm x 0.76mm: the ‘normal’ size used by most older smartphones and mobile devices. Although newer phones and tablets are now using smaller form factors, devices like cars, vending machines, and others are still using 2FF SIM cards.
- 3FF (Micro-SIM), 15mm x 12mm x 0.76mm: roughly half the size of the Mini-SIM, used in various mobile terminals and IoT devices.
- 4FF (Nano-SIM), 12.3mm × 8.8mm × 0.67mm: the smallest SIM that comes in the form of physical cards, used in wearables like smartwatches and many IoT devices. Since they are small, they allow more versatility in device design to accommodate bigger batteries or slimmer/smaller designs.
- MFF (eSIM), 5mm x 6 mm x 1mm: The eSIM stands for embedded SIM, and is no longer a physical card but rather is a chip that is embedded (soldered) to the device. The eSIM is designed to be rewritable, so it can be written over and provisioned remotely.
M2M SIM cards are essential in any IoT deployments with cellular connectivity, offering more versatility and seamless networking than traditional SIM cards. The M2M SIM cards won’t only provide the connectivity required by the IoT deployment, but also will help minimize common issues in IoT projects, especially in large-scale deployments that involve multiple locations.