SIM Types & Form Factors
IoT SIM
An IoT SIM (Internet of Things SIM) is a special type of mobile SIM card designed for connected devices rather than phones. It supports reliable, long-term data transmission for sensors, trackers, cameras, meters, and industrial equipment. Unlike consumer SIMs, IoT SIMs often offer fixed IP, roaming, or multi-network capabilities, with advanced management and security features.
Roaming SIM
A SIM card that can connect to multiple mobile networks across different countries or regions, automatically switching to the strongest signal. Ideal for global or rural deployments.
Multi-Network SIM
Allows connectivity to multiple mobile operators within the same country or across borders, improving coverage and redundancy for mission-critical applications.
Fixed IP SIM
A SIM with a static public or private IP address, enabling direct remote access to routers, cameras, and industrial systems without dynamic IP complications. Fixed IP SIM card was the dominant terms for the majority of M2M connectivity SIM cards.
Private IP SIM
Provides a static, non-public IP address, ideal for internal or secure systems that communicate only over private networks or via VPNs.
Public Dynamic IP SIM
A standard mobile SIM that is dynamically assigned an IP address each time it connects to the network. Suitable for general internet access but less ideal for remote management.
eSIM (Embedded SIM)
A small embedded chip soldered into a device that can be remotely programmed with multiple carrier profiles. Reduces SIM swapping and increases deployment flexibility. Many leading manufacturers are now including eSIM connectivity in their routers like Teltonika and their RUT241 eSIM.
eUICC (Embedded Universal Integrated Circuit Card)
The technology behind eSIMs that allows over-the-air profile provisioning and switching. Essential for global and scalable IoT rollouts.
eSIM with eUICC
Together they enable remote network management—switching operator profiles without replacing physical SIMs, which is vital for international and hard-to-reach deployments.
iSIM (Integrated SIM)
Integrated directly into the device’s processor, iSIMs offer enhanced security, lower power consumption, and no physical interface, suitable for compact and secure IoT applications.
SoftSIM
A virtual SIM embedded entirely in software, without any hardware element. Offers theoretical flexibility but is still emerging in commercial use.
SIM Form Factors
Standard SIM sizes include Mini (2FF), Micro (3FF), Nano (4FF), and MFF2 (eSIM soldered). Devices vary in their required form factor depending on size and durability needs.
Multi-IMSI SIM / Dual IMSI
Holds multiple mobile network profiles and switches between them dynamically to maintain the best available coverage, ideal for fleet and global asset tracking. These Multi IMSI / Dual IMSI IoT SIM solutions provide the ultimate in connectivity resilience.
SIM Management Platform
A cloud dashboard that lets businesses manage their SIM fleet—activations, data usage, alerts, and network changes—all from one interface.
Programmable SIM
Allows real-time changes to network preferences, data usage limits, and device controls. Often used in managed IoT solutions for dynamic environments.
Mobile Network Technologies
2G (GSM)
An early mobile network standard offering basic SMS and low-bandwidth data. Still used in some legacy IoT devices, though being phased out globally.
3G (UMTS)
Provides better speeds than 2G and supports voice and basic data services. Currently in the process of being decommissioned in many regions.
3G Sunset
The gradual shutdown of 3G networks (3G Sunset), pushing businesses to upgrade IoT systems to LTE or 5G-compatible technologies.
4G LTE (Long-Term Evolution)
The standard for modern mobile data, offering fast speeds and robust performance for IoT, CCTV, and mobile broadband.
LTE-A (LTE Advanced)
An enhancement of LTE with features like carrier aggregation and higher capacity. Often branded as 4G+ or LTE Pro.
LTE-M (Cat-M1)
A low-power cellular standard optimized for IoT. Offers reduced bandwidth but increased battery life and better building penetration.
NB-IoT (Narrowband IoT)
Specially designed for low-data, low-power, long-battery-life IoT applications like smart meters, sensors, and trackers.
NTN NB‑IoT (Non-Terrestrial Network Narrowband IoT)
A satellite-enabled extension of NB‑IoT technology that provides low-power, wide-area IoT connectivity in regions without terrestrial mobile coverage. Operating via Low Earth Orbit satellites or high-altitude platforms, NTN NB‑IoT enables global communication for remote sensors, trackers, and other IoT devices using compact antennas and narrowband frequencies. Ideal for use cases in agriculture, logistics, marine, and environmental monitoring.
Cat 1 / Cat 1bis
Moderate-speed LTE modules used in many mid-range IoT applications where full LTE is not required.
Cat 6 / Cat 12 / Cat 20
Indicates the LTE category class, each supporting different speeds, antenna requirements, and latency for varying use cases.
5G NR (New Radio)
The standard for 5G networks—offering massive bandwidth, low latency, and high reliability for industrial automation, smart cities, and real-time control.
5G SA (Standalone)
A pure 5G network architecture with its own core infrastructure. Delivers ultra-low latency and the full benefits of 5G.
5G NSA (Non-Standalone)
Uses existing 4G infrastructure for signalling while adding 5G data channels. Easier to deploy, often the first phase of 5G rollout.
Private 5G
A dedicated 5G network owned by an enterprise. Enables complete control, ultra-low latency, and secure data flow across private infrastructure.
DSS (Dynamic Spectrum Sharing)
Allows LTE and 5G to operate on the same frequency band, helping carriers migrate users gradually while maximising existing spectrum.
LoRa (Long Range)
A non-cellular, low-power wireless technology for long-range communication. Excellent for rural or battery-powered IoT deployments.
LoRaWAN
A network protocol built on LoRa, enabling encrypted, low-bandwidth, long-range communication between IoT devices and gateways.
LPWAN (Low Power Wide Area Network)
Covers multiple long-range, low-power network types like LoRaWAN, Sigfox, and NB-IoT. Ideal for battery-operated sensors over wide areas.
MIMO (Multiple Input, Multiple Output)
A wireless technology using multiple antennas to increase speed and reliability. Often used in LTE-A and 5G routers.
VoLTE (Voice over LTE)
Allows high-quality voice calls over 4G data networks. VoLTE is critical as 3G voice networks are phased out (2G and 3G Sunset).
VoNR (Voice over New Radio)
Delivers voice calls natively over 5G SA networks, enabling future-proof communication for connected devices.
Router, Hardware & Protocol Terms
Modem
A device that connects directly to the mobile network using a SIM card. Often built into routers or gateways.
Router
Creates a local network by sharing mobile data from a SIM (via a modem). Connects multiple devices via Ethernet or Wi-Fi.
Gateway
A router with added intelligence, translating between IoT device protocols and networks like MQTT, Modbus, or HTTP.
Serial RS232
A legacy communication port used to connect industrial devices like sensors or PLCs to a gateway.
Serial RS485
A multi-device, long-distance communication standard, still widely used in industrial environments.
Digital I/O (Input/Output)
Ports on IoT gateways that send or receive binary signals. Used for alarms, sensors, or triggering relays.
Analog I/O
Handles variable signal levels, useful for sensing temperature, pressure, or voltage changes.
MQTT (Message Queuing Telemetry Transport)
A lightweight, low-overhead protocol ideal for IoT device communication. Uses a publish/subscribe model for efficient data flow. ( MQTT )
Modbus RTU / TCP
A serial (RTU) or network (TCP) communication protocol used in industrial equipment for monitoring and control.
CAN Bus
Used in automotive and industrial environments for communication between microcontrollers and devices without a host computer.
OpenVPN
A secure, encrypted tunneling protocol used by IoT routers to create safe links to remote networks.
L2TP / IPsec
Tunneling protocols used to establish VPNs for secure communication between devices and servers.
Zero-Touch Provisioning
Automatically configures routers or gateways when they first connect to the network—reducing setup time.
Monitoring, Deployment & Connectivity
SIM Lifecycle Management
The process of provisioning, activating, suspending, and terminating SIMs across a fleet—vital for cost and security control.
SIM Steering
Controls which network a multi-network SIM should prefer, often based on cost, signal quality, or policy rules.
APN (Access Point Name)
A configuration setting that defines how a SIM card connects to the network. Determines routing to public internet or private VPN.
Private APN
Creates a secure tunnel from the device to the corporate network without exposing traffic to the public internet.
VPN (Virtual Private Network)
Encrypts data between IoT devices and the core network—critical for security, especially in public IP deployments.
IPSec Tunnel
A secure protocol suite for authenticating and encrypting IP packets—used in many IoT VPN solutions.
Port Forwarding
Enables external access to specific ports on a device behind a mobile router with a public IP—often used for CCTV and remote monitoring. ( Port Forwarding )
Ping Monitoring
Periodically checks if a device is online or reachable. Used to detect outages or remote device failures.
Signal Strength (RSSI / RSRP / SINR)
Measures cellular connectivity: RSSI (signal power), RSRP (reference signal), and SINR (quality). Used for diagnostics and antenna positioning. Read about Signal Strength and how it affects your M2M / IoT installation.
Failover SIM
A secondary SIM that automatically activates if the primary connection fails—ensures resilience in critical deployments.
Load Balancing
Distributes traffic across multiple SIMs or WAN links to optimise performance and reliability.
Bonding
Combines multiple mobile or WAN connections into a single fast, resilient virtual line.
Data Pooling
Allows multiple SIMs to share a collective data allowance—reducing waste and managing usage more efficiently.
Usage Alerts
Triggers when a SIM approaches its data limit—helping to prevent overage costs or unexpected usage spikes.
Remote Firmware Update
Pushes software updates to routers or gateways without on-site access—reduces maintenance and keeps devices secure.
Zero Trust Architecture
A security model where devices are never trusted by default, even if already inside the network perimeter.
IoT Device Whitelisting
Only approved devices can connect to the network, preventing rogue devices from using SIM data or accessing systems.
Data Throttling
A reduction in data speeds after a set usage threshold. Often applies to consumer SIMs but not M2M SIMs.
IMEI Locking
Restricts a SIM to work only in a specific device, adding a layer of anti-theft and usage control.
Heartbeat Monitoring
A scheduled check-in from a device to confirm it’s still operational. Often includes location, signal, or data usage stats.
Applications & Use Cases
Smart Metering
SIM-enabled water, gas, or electricity meters send real-time usage data to the utility company, eliminating manual readings.
Vehicle Telematics
SIMs in fleet vehicles provide GPS tracking, engine diagnostics, and driver behaviour analytics in real time.
Remote CCTV
Cellular routers with fixed IP SIMs enable 24/7 remote access to video streams from construction sites, car parks, and rural premises.
Point of Sale (POS)
4G/5G SIMs ensure reliable transactions for tills, kiosks, and vending machines in pop-up or mobile locations.
Smart Agriculture
Sensors monitor soil moisture, livestock, or weather conditions, using cellular IoT to report data for better yield and sustainability.
Healthcare Monitoring
SIM-connected wearables or devices transmit patient vitals in real time—useful for home care, elderly monitoring, and diagnostics.
Smart Buildings
Connected sensors control HVAC, lighting, and security across commercial sites—streamlining management via cloud dashboards.
Industrial Automation
Factories use cellular SIMs in PLCs and SCADA systems to monitor and adjust machinery from remote control rooms.
Temporary Internet (Events)
Fast-to-deploy 4G/5G routers with business SIMs create pop-up connectivity for events, film crews, or disaster recovery.
IoT Smart Grid
SIMs in energy infrastructure transmit data from substations, transformers, and sensors for real-time grid management.
Railway
In the context of connectivity and IoT, Railway refers to communication systems, devices, and equipment approved for use in railway environments. These typically meet strict safety, vibration, temperature, and electromagnetic standards (like EN 50155). Railway-approved routers, SIMs, and antennas are used for passenger Wi-Fi, signalling, CCTV, and real-time operational monitoring across trains and infrastructure.