1. Sixfab SIM Activation

This step is applicable only when the Sixfab SIM card is used. If a third-party SIM card is used, this step should be skipped.

To register and activate the Sixfab SIM card, the steps described in the tutorial linked here.

2. Cellular Internet Connection

This section describes the available methods for establishing a cellular internet connection on single-board computers such as Raspberry Pi using cellular modules.

Depending on the hardware, chipset and deployment requirements, any of the methods below can be used. All approaches provide cellular internet connectivity but differ in configuration complexity, performance characteristics and level of control. The appropriate method can be selected based on project needs.

2.1 Cellular Internet Connection in ECM Mode

ECM (Ethernet Control Model) is one of the simplest methods for enabling a cellular internet connection. In this mode, the cellular module presents itself as a standard USB Ethernet device.

ECM is natively supported by the Linux kernel and does not require additional driver installation. Once connected, the operating system automatically detects the module as a network interface, making this method suitable for rapid and straightforward deployments. Applicable with Quectel and Telit modules.

Documentation: Cellular Internet Connection in ECM Mode

2.2 Setting up a data connection over QMI interface using libqmiSetting up a data connection over QMI interface using libqmi

Cellular modules based on Qualcomm chipsets support the QMI (Qualcomm MSM Interface). Using libqmi, you can establish a robust and configurable data connection.

This method works with modules such as Quectel EC25, EG25-G, EC21, UC20-G and Telit LE910C1 / LE910C4 when used with the Raspberry Pi 3G/4G & LTE Base HAT.

While the setup is slightly more advanced than ECM, it provides greater control over modem behavior and connection parameters. Applicable with Quectel and Telit modules.

Documentation: Setting up a data connection over QMI interface using libqmi

2.3 Quectel CM Tool - Introduction and Setup Guide

quectel-cm is a connection management tool provided by Quectel for establishing and maintaining cellular data connections. It automatically handles network registration, IP address assignment, DNS configuration, and routing.

Sixfab currently stocks EG25 / EC25 series and RM502Q series modules, all of which are supported by quectel-cm. Additionally, quectel-cm supports most Quectel cellular modules beyond the Sixfab product lineup.

This method provides a balance between ease of use and operational control and is commonly used in production environments. Applicable with Quectel modules only.

Documentation: Quectel CM Tool - Introduction and Setup Guide

3. Remote Access for Raspberry Pi

Once Raspberry Pi is connected to the internet, it can access and manage remotely without physical access. This is especially useful for headless setups or devices connected via cellular networks.

Available Remote Access Options

Raspberry Pi Connect An official Raspberry Pi service that provides secure, browser-based terminal and file access without manual network configuration.
Remote.it Allows secure remote access without port forwarding. Works well behind NAT or cellular networks and supports SSH, VNC, and web services.
Tailscale Establishes a secure private network that allows devices to access the Raspberry Pi as if they were on the same local network.