Chapter 7 - Using Linux With The L4G2D Radio; Overview; Pre-Requisites; Modem Manager And Network Manager Applications - Multitech MultiConnect MTC-L4G2D User Manual

Chapter 7 – Using Linux with the L4G2D Radio

Overview

L4G2D products use a Telit LE910C4-WWX radio that provides USB serial and binary interfaces to communicate
with an operating system's TCP/IP networking subsystem.
This section uses Raspberry Pi Raspberian distribution to show how to use AT Commands and PPP (serial) or the
Qualcomm Media Interface (QMI, binary) to configure and bring up a Linux network interface for communicating
over the cellular data network.
If you use a different Linux distribution, the provided examples may need adjustments for your application.

Pre-Requisites

Information in this chapter assumes the following:
Knowledge of Linux networking, command line tools, and the underlying TCP/IP network protocols.
Working computer hardware and OS.
Working SIM and cellular account provisioned by the cellular carrier for an IoT device (refer to carrier for
details.)
Working MultiTech L4G2D hardware.

Modem Manager and Network Manager Applications

Modem Manager and Network Manager are Linux applications used to manage the connection state for the
modem hardware and network interface respectively.
Linux examples in this application note assume Modem Manager and Network Manager are disabled or not
installed.
Note: Modem Manager and Network Manager may successfully connect to the cellular network using Linux
distribution specific defaults. If does not, consult the application specific documentation or reach out to the
relevant open source communities for more information.

USB Interfaces

The Telit radio module in the L4G2D provides three USB-based interfaces: two AT command interfaces and one
QMI interface.

Device File Names Persistence After Modem Power Cycle or Reboot

Usually modem device file names in /dev correspond with the same USB interfaces after the modem reboots or
power cycles. However, the kernel module and related kernel subsystems do not guarantee a USB interface and a
device file name will correspond every time the modem is rebooted or power cycled.

AT Command Interface

The AT Command interface provides a text based serial protocol used to configure and issue commands to the
modem to implement functionality.
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MultiConnect Cell MTC-L4G2D User Guide
USING LINUX WITH THE L4G2D RADIO
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