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What IoT SIM Cards Are and How Do They Work in IoT Devices

IoT (Internet of Things) devices sometimes use an IoT SIM card, also known as M2M SIM Cards (machine-to-machine), for data connectivity enabling remote devices to send and receive information by establishing a wireless cellular connection to a 2G, 3G, 4G (full LTE or Cat-M or NB-IoT) or 5G network.

IoT SIM Cards differ from traditional SIM cards because they are typically data and SMS while Travel SIM cards offer Voice, Data and SMS. Form factor is another way IoT SIM cards differ from travel SIMs. We will discuss form factors a little later.

Another differentiation from travel SIM cards is the other features that IoT SIMs offer. These include, but aren’t limited to:

  • Private APN
  • VPN
  • Static IP addresses
  • IMEI Locking
  • IP filtering
  • Feature-rich management portal

When it comes to data plans, there are essentially two types: Pay-As-You-Go (or PAYG) and Pooled data plans. Either plan type are often offered on prepaid and postpaid service plans. IoT Data plans are usually billed on a monthly basis, but some providers will lock you into a longer contract (a year or longer) with activation and early termination fees.

Security codes and credentials that identify the carrier, and SIM card are stored on the M2M SIM card’s UICC which stands for Universal Integrated Circuit Cards. The newer standard is the eUICC which enables IMSI (International Mobile Subscriber Identity) changing Over The Air (OTA). Every linked device, whether they are on or off the network, everywhere in the world, has a specific IMSI number (or  multi-IMSI’s) which is used by the SIM card to verify it’s its ability to attach to cellular networks. IoT SIM cards run an applet that transmits that identity data to a cellular modem. The actual network attachment is carried out by the modem, sometimes also referred to as “radio” or “radio module”. 

The best IoT SIM card technology offers access across many networks and global access without requiring individual cards for each carrier and for each country in order to support global IoT deployments anywhere in the world. But this isn’t always the case. Global SIM cards can either be “steered” or “no steering”:

  • A steered IoT SIM Card is set up where the home operator makes use of global alliances to grant access to particular networks for each visited nation or region using a Preferred Roaming List (PRL). Steered SIMs will usually use less networks in a particular region than no steering SIM cards. Having no backup networks in the event of outages or shifting partner agreements, causes these SIM cards to often lose the IoT connection and lack stability to operate IoT systems successfully because Steered IoT SIM cards will stay connected to the “preferred” network even when there is almost no coverage. This makes the connection slow and unstable. Additionally, the M2M device deployment company has no influence on the networks that the linked devices can employ. Carriers use steering to reduce their costs, but they do this at the expense of the customer.


  • No Steering IoT  SIM card architecture uses all available networks allowed by the IMSI simultaneously.. Each IMSI on these SIM cards provides access to a number of networks, usually hundreds, around the world. The home network does not have a PRL where they steer traffic to particular networks; they allow the device to make the decision as to which network the SIM connects. This ensures that the device is always connected to the the best network in that location at that point in time. No Steering is the best choice for the customer for redundancy and stability. 

Various dimensions or shape factors are available for IoT SIM cards.

Traditional, plastic, removable IoT SIM cards are available in  form factors. These are Mini (2FF), Micro (3FF), Nano (4FF) and embedded chips. These can be punched with one, two, or all three sizes available on a single card.

These three SIM form factors can be too large to be useful as IoT device types become smaller in size, like wearables. Embedded SIMs (MFF2 form factor), as opposed to plastic SIM cards, are the choice form factor these solutions. They are directly placed and soldered onto the circuit board (PCB). The MFF2 form factor, a 6x5mm microchip soldered to the circuit board, is the most popular for embedded SIMs.

What kinds of IoT devices are examples?

In general, IoT devices are any hardware device with an data connection that remotely transmits data without any human interaction. They can be fully autonomous. Of course, because they are connected, they can also be interacted with by administrators. The number of use cases is vast. Several industries include, include, but by no means are limited to, Transportation & Logistics, Public Sector, Environmental Science, Finance and Insurance (like Usage Based Insurance), Agriculture (Agtech), Healthcare, Retail, Manufacturing, Utilities and Energy, Real Estate, Automotive, and Aviation..

Some connected device examples include:

  1. For Utilities: Pipes, valves, batteries, tanks, wind turbines, solar panels, electrical poles, meters, and staff tablets;.
  2. Health care: Medical devices, implants Telehealth, medicine dispensers, and staff tablets;
  3. In retail: POS devices and terminals, Inventory control, temperature monitoring, and vending machines;
  4. Manufacturing: Materials, containers, completed products, trucks, factory equipment, worker wearables, robotics, and warehouse machinery;
  5. Public Sector & Facilities Management: Water treatment, forest management, HVAC, lighting, air quality sensors, elevators, waste management, parking meters, locks, surveillance equipment, signage digital, and kiosks; 
  6. Real estate or intelligent homes: Cameras, thermostats, lock boxes, locks, lights, media, kitchen devices;
  7. Agtech: Irrigation and tractor systems, livestock tracking, and farming other equipment.

OneSimCard IoT, https://iot.onesimcard.com/, offers cutting-edge, multi-IMSI IoT SIM cards that offers choice and control while granting access to worldwide M2M networks. Take a look at our solutions to get a sense of the use cases our clients are currently employing our solution. You can also fill out the Contact Form to speak with one of our IoT experts.