Powerful indoor LoRaWAN gateway with GSM support

December 13, 2018

The Kerlink Wirnet iFemtoCell Gateway is a powerful and affordable indoor LoRaWAN gateway. It is ideally suited to the expansion of existing wireless networks, e.g. Connectivity to poorly accessible locations. In addition, new LoRaWAN radio networks can be set up quickly and economically.

It provides an open developer framework for software extensions and runs on a standard Linux operating system.

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Product name:Kerlink Wirnet iFemtoCell
Category:LoRaWAN Gateway
1 rue Jacqueline Auriol


The most important features at a glance

  • LoRa / LoRaWAN™ 1.0.1
  • Power supply: external 12V power supply
  • Semtech SX1301 LoRa chip with 49 x LORA demodulators and 1x (G) FSK demodulator
  • 2x Semtech SX1257 transceivers
  • internal WLAN antenna
  • SMA connector for external LoRa antenna, supplied with: 3dBi dipole antenna
  • Dimensions: housing without LoRa antenna: 160x90x35mm
  • Certifications: EN 300 220

Unboxing – housing and processing

The iFemtoCell Gateway has a white PC/ABS housing. It can be fixed to a wall with 2 screws. The dimensions of the housing with the supplied antenna are 220 x 125 x 35 mm.

The gateway is powered by a supplied, external 12V power supply. The complete weight of Gateway, detachable antenna and external power supply is 280g.










The gateway has

  • an SMA connector for the external LoRa antenna
  • an RJ45 connector for Ethernet cabling
  • a USB port for firmware updates and GSM/3G/4G dongles
  • a DC jack for the external power supply
  • 3x two-color LEDs with the following meanings:

LED 1:

  • Red, flashing: Kernel booting
  • Green, flashing: System booting
  • Green, permanently lit: booting finished, gateway is running

LED 2:

  • Red, permanently lit: Packet Forwarder not connected/faulty
  • Green, flashing: Packet Forwarder connecting
  • Green, permanently lit: Packet Forwarder is connected

LED 3:

  • Red, permanently lit: Gateway booting
  • Green, flashing: Receiving LoRa messages
  • Red, flashing: sending LoRa messages

Configuration and operation

The Wirnet iFemtoCell Gateway supports two types of operation:

  • Operation via the Kerlink Wanesy Management Center (WMC)
  • Operation via any LoRa network server

Since the Wirnet iFemtoCell Gateway is based on a standard Linux operating system with access via SSH, the software components can be easily exchanged/updated. The essential packages are:

  • Operating system (firmware)
  • Packet Forwarder und HAL (Hardware Abstraction Layer)
  • Optional: VPN tunnel package

For operating through the Wanesy Management Center (WMC), Kerlink introduces the WMC Wik (Registration required for access) a complete software package. This includes firmware, packet forwarder + HAL and VPN tunnel software.

If this software package is installed, the gateway can be easily managed, controlled and updated via the WMC. The LoRa messages can be received in the WMC and/or forwarded to third-party LoRa application servers.

The use of the Kerlink WMC requires a registration and user fee. The fees are calculated individually by Kerlink.

For operation with aLoRa network server third-party manufacturers (such as Smartmakers ThingsHUB, TTN, Loriot, etc.) Kerlink also provide the necessary software components such as firmware and packet forwarder + HAL. The documentation and the download takes place via the Wirnet iFemtoCell Wiki.

For access, registration with Kerlink is also necessary.

In addition to the software packages provided and coordinated by Kerlink, the Wirnet iFemtoCell Gateway also allows the execution of own code in the form of compiled programs or scripts. Herewith the functionality of the gateway can be added to or altered as desired.

Forcompiling own applications Kerlink provides a toolchain as well as libraries and header files. Because the Wirnet iFemtoCell Gateway does not contain an embedded compiler, compilation must be done on a separate PC.

The tutorial and the files provided can also be downloaded from the Wirnet iFemtoCell Wiki.

In the following section, we will explain the easiest and fastest way to upgrade the Wirnet iFemtoCell Gateway to the latest software version for operation on any LoRa network server. to be updated. At the time of the test, this was the “Wirnet iFemtoCell Firmware v3.4.5 (September 2018)” along with the “Semtech Packet Forwarder v3.1.0-klk18 (June 2018)”.

“Hands-on” – the how-to in individual steps

Depending on the software version of the delivery status, the firmware update of the gateway can be done via LAN, USB or WLAN. A significant version jump was from version 3.3.x to 3.4.5. In this version jump, the access data and the sequence of updates with several update files were changed.

In order to carry out an update independently of the delivered version and without previous knowledge, the following way is available:

  • Update the operating system firmware via a USB stick
  • Subsequent update of the packet forwarder + HAL via WLAN and web browser

Since the Wirnet iFemtoCell Gateway provides for an update via USB in all firmware versions, the USB stick can be prepared and used according to the following instructions without having to connect to the gateway via the network in order to upload files or read out versions.

For the firmware update, the following files must be copied to an empty (FAT32 formatted) USB stick:

  • usb.autorun: this script is executed when inserting the USB stick
  • usbkey.txt Password checked before executing usb.autorun
  • keros_x.y.z.ipk: the actual firmware package

A working template for the content of the usb autorun“Script is provided in the Wirnet iFemtoCell Wiki. This script will only run after the password from the “usbkey.txt” file was successfully checked. The password can be used to prevent anyone from downloading updates to the gateway. On delivery, the default password is “USBklkPassword”. Details on how to change the password afterwards can be found also in the Wiki of Kerlink.

If the password has been checked successfully, the firmware update is carried out to the new version. The gateway plays the operating system and then restarts. The three LEDs always indicate the current status during this process. For the meaning of the LED colors see above.

Once the new firmware has been installed and the gateway has been restarted (LED1 permanent green), the update of the packet forwarder can now be carried out conveniently via the web browser. The firmware versions as of 3.4.4 open a temporary configuration WLAN for a short time after restarting the gateway. It can be found under the SSID “klk-wifc-xxxxxx”, where the last 6 characters (xxxxx) represent the last 6 characters of the board ID of the Wirnet iFemtoCell Gateway. This can be found on the sticker on the bottom.

For the connection to the protected WLAN, the MAC address of the gateway must be used as password. The MAC address is also on the label on the bottom of the gateway and must be entered without spaces/special characters. The connection with the Wirnet iFemtoCell WLAN takes a moment. The PC from which the connection is established gets an IPv6 IP address assigned, but no gateway or DNS server. IP address assigned but no gateway or DNS server. Ts means the pc can keep its normal LAN connections, as there is no IPv.4 address conflict of IP addresses typically used in local area networks. A meaningful implementation of Kerlink!

If you are connected to the iFemtoCell WLAN, the configuration interface can be reached via the URL or rather the name “klk-wifc”.

The access data from version 3.4.4 are: “admin” / “pwd4admin”

Under the menu item “Administration / Update”, any software packages in “.ipk” format can now be loaded by drag & drop.

The necessary file for the packet forwarder is provided by Kerlink The standard Semtech Packet Forwarder (SPF) is used here, which sends the LoRa packets via UDP to the LoRa network server (LNS) and is therefore compatible with most existing LNSs.

IIn the test the file “spf_3.1.0-klk18_4.1.3-klk11_klk_wifc.ipk” was successfully uploaded. The updating process was clearly displayed.

After completing the import of the packet forwarder, the gateway should be restarted via the web interface.

Unfortunately, the version of the packet forwarder is not displayed next to the other information.

It is a pity that the configuration of the Semtech Packet Forwarder can not be done via the web interface. For this step you have to connect to Wi-Fi or LAN and SSH with the gateway and the settings in the usual file “global_conf.json” on the command line.

The LAN IP address can be read on the web interface under “Overview / Network status”.

The SSH access can be done with the access data “root” / “pdmk-xxxxxx”, where the last 6 characters of the password again correspond to the last 6 characters of the board ID (sticker on the bottom)

GSM / LTE Modem

The Wirnet iFemtoCell Gateway offers the use of an external GSM USB dongle for the Internet connection. A list of supported models can be found at http://wikikerlink.fr/wirnet-ifemtocell/doku.php?id=wirnet-ifemtocell:cellular_backhaul

For our test we used the most popular modem in Germany, the M2M Huawei MS2372h-153. After we inserted the (Telekom) iSIM card nto the GSM dongle, plugged the dongle into the USB port of the gateway and restarted the gateway, the dongle was immediately recognized.

A USB extension cable must be used for the USB connection, as the dongle cannot be plugged directly into the gateway due to the protruding housing.

If the dongle was recognized successfully, the access parameters such as PIN, APN, etc. can be conveniently entered in the web interface.


The Kerlink Wirnet iFemtoCell Gateway is a flexible and cost-ective LoRaWAN indoor gateway. The configuration for using the Kerlink LoRa Network Server “Wanesy Management Center (WMC)” is simple and convenient. All necessary software components are provided on the Kerlink Wiki to connect to any third-party LoRa Network Server (LNS),. Users of the widely used Kerlink Wirnet Station quickly become familiar with the Wirnet iFemtoCell. The Linux environment and the configuration files are very similar. The widely used Semtech Packet Forwarder can be comfortably deployed and updated via a web browser via drag & drop, but the configuration must be done via the SSH console.

The built-in WLAN for configuration / administration is comfortable. Here it would be desirable that the configuration files of the packet forwarder could be changed and that it be indicated which software version was loaded.

The GSM dongle hardware support worked right away in the test. The configuration of the PIN, APN, etc. via the web interface is convenient. The need for a USB extension cable to physically connect the GSM dongle with the gateway is disturbing.


The Kerlink Wirnet iFemtoCell is now available in our online shop thingsHUB Market.


If you want to learn more about commissioning, read the guest article by Dr. Claus Kühnel, Inter alia,, he describes how the LoRaWAN Gateway Kerlink Wirnet iFemtoCell is configured for use with TTN and LORIOT LNS.

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