TECHSHIP IS A GLOBAL SUPPLIER OF WIRELESS COMPONENTS
Telit LN941 is a CAT-6 module for the European market in M.2 format.
Compliant with 3GPP Category 6 releases LN941 is the most affordable LTE module, with the capability of 2CC Carrier Aggregation, reaching up to 300Mbps DL.
The Telit M.2 family of modules supports the latest LTEAdvanced
networks with 3G fallback.
The industrial-grade PCIe M.2 form factor allows for easy integration
into mobile computing, networking, and industrial IoT device platforms that command a smaller and thinner footprint.
This user guide describes how the intergration of Telit LN940 series cellular modules are performed in Linux environments.
This archive contains the Telit LN94x series Linux drivers Driver Package and patching guides if needed due to kernel versions and feature support
This archive contains the Telit LN94x Series AT Commands over MBIM Interface Helper Tool and manual
This archive contains the LN940 driver installer for Windows 10 systems.
How to step by step set up a data connection over QMI interface using qmicli and in-kernel driver qmi_wwan in Linux?
Several cellular modules based on Qualcomm chipsets implements the Qualcomm Qualcomm MSM (QMI) Interface.
There is a open source Linux in-kernel driver supporting this interface and it is called qmi_wwan. The library libqmi can be used to communicate with the cellular devices over the interface and do necessary configurations to trigger the data connection over the cellular network.
Sierra Wireless MC74**/EM74** series: requires RAW-IP configuration.
Sierra Wireless EM75** series: requires RAW-IP configuration.
Telit LM940: requires RAW-IP configuration.
Telit LN94x series: requires RAW-IP configuration.
Simcom SIM7500/SIM7600/SIM7600*-H series: requires RAW-IP configuration (supported in qmi_wwan driver kernel 4.18+).
Simcom SIM7100 series: 802.3 IP framing supported.
Sierra Wireless MC73**/EM73** series: 802.3 IP framing supported.
First install the libqmi Linux library e.g. by using your system package manager like apt etc. (more details about libqmi here: https://www.freedesktop.org/wiki/Software/libqmi/)
Verify that you have the Linux in-kernel qmi_wwan driver installed for the cellular modules exposed QMI interface endpoint over USB:
Can look e.g. like this:
|__ Port 1: Dev 3, If 2, Class=Vendor Specific Class, Driver=qmi_wwan, 480M
If the driver is not correctly loaded, please verify that the module is set to expose the correct USB endpoints configuration toward the host system and that you have followed the provided guides from the cellular module vendors, regarding how to implement the module in Linux.
Libqmi expose a command line interface that can be used to communication with the module over QMI interface.
The qmicli help will output information about all commands available:
The cellular modules QMI control interface are usually named cdc-wdm* e.g.:
In order to allow parallel commands to be execute on the module over QMI interface, it is recommended to use the libqmi proxy function. This can be done by including the attribute -p or --device-open-proxy in every qmicli command.
If a SIM pin is required for the SIM card, use command bellow:
qmicli --device=/dev/cdc-wdm0 -p --dms-uim-verify-pin=PIN,1234
The name of the related network interface to QMI control channel can be acquired with the command:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --get-wwan-iface
The most recent Qualcomm based cellular modules only expose QMI interfaces that can support Raw-IP mode. Sierra Wireless EM/MC74 and EM75 series modules, Telit LM940 and LN940 series for example require this.
Check what IP-mode the host system is configured for:
qmicli --device=/dev/cdc-wdm0 --get-expected-data-format
Check what IP-mode the cellular module require:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wda-get-data-format
to change qmi_wwan driver to use Raw-IP.
Disable the network interfaces exposed by the cellular module:
ip link set dev wwan0 down
Trigger the Raw-IP support:
echo Y > /sys/class/net/wwan0/qmi/raw_ip
Enable the network interfaces again:
ip link set dev wwan0 up
Now the data connection in the cellular module can be activated e.g. with a IPv4 type configuration on the specified APN:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-start-network="ip-type=4,apn=data.tre.se" --client-no-release-cid
Once "Network started" is displayed, you can send a DHCP request on the network interface.
Please note that not all DHCP clients in Linux can support Raw-IP format, udhcpc however support this for IPv4 over Raw-IP.
udhcpc -q -f -n -i wwan0
Disconnect the data bearer and data connection over QMI by command bellow and providing the network handle and CID returned at connection activation:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-stop-network=NETWORK_HANDLE --client-cid=CID
Additional useful commands:
Request module manufacturer:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --dms-get-manufacturer
Get module model:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --dms-get-model
Get firmware version:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --dms-get-revision
Get module IDs (IMEI etc.):
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --dms-get-ids
Get SIM card status:
qmicli --device=/dev/cdc-wdm0 --device-open-proxy --uim-get-card-status
Recent cellular modules like Sierra Wireless EM7565 require at least libqmi V1.20. Check version with command:
If the connection was successfully set up established, you now have data connectivity. A ping to a remote server using the cellular network interface can for example prove this:
ping -I wwan0 220.127.116.11
The ifconfig Linux tool can show the current details for the network interface:
libqmi is well integrated and supported in ModemManager tool for Linux. ModemManager again is well integrated and supported when using NetworkManager tool in Linux. Please note however that these two tools expect the cellular module interfaces to only be used by them so if you manually want to use the libqmi library or AT commands interfaces, please turn off/disable ModemManager and NetworkManager first.
The libqmi is a generic open source library for Linux systems and QMI protocol from Qualcomm, therefor there are several commands only working on selected devices and not necessarily on supported in the specific device you use, resulting in an error message.