Axon LTE

Looking for a guide how to get started with LTE on Mervis IDE? Please see this tutorial, otherwise continue here.

Axon series controllers are shipped with the Mervis image by default. Mervis can be disabled or you can flash the open-source image manually.

This manual refers to the LTE series of Axon units (currently S165, M565 and M265).

  1. Insert a micro-sim supporting LTE data into the slot.
  2. Log-in to the controller via SSH (or SCP).
  3. Install unipi-lte package:
    sudo su
    apt-get update
    apt-get install unipi-lte
  4. Edit file /etc/unipi/lte.conf. APN setting is mandatory (LTE service is turned off if this line in the file is missing or is commented). You can use built-in nano editor to do this. The APN parameter should be provided by your network operator, so internet is the default value.
  5. In the same way, set the PIN parameter if SIM is PIN-protected.
  6. Restart your controller. Be patient, registration to the mobile network can take tens of seconds. When registered, NET LED lights up.
  7. During normal operation, “Mobile network” LED indicators SIM, NET, INT should be ON while blinking SIG indicates signal strength.
  8. In case of any problem, check the Syslog for more info (you can use grep command to filter messages from the unipi-lte service).

Autoswitch feature

By default, the unipi-lte Linux service provides automatic handling with the default network gateway according to the WAN availability on both main and backup network interfaces. The main network adapter is usually wired ethernet (eth0) while the backup is realized by the LTE modem. In the Linux routing table, the default GW routes for both of these interfaces should be always present. When a “swap” of these interfaces is necessary, the unipi-lte daemon automatically increases/decreases their metrics.

Therefore, it is necessary to continually keep the metrics as positive non-zero values. This is ensured by a DHCP client when DHCP is active on the main network interface but it must be assured manually if static IP is configured on the main interface (as static routes have zero metrics as default). As an example, you can put a constant to the interface’s configuration file at /etw/network/interfaces.d.

Then, the /etw/network/interfaces.d/eth0 file for static IP configuration may look like:

# Example static IP configuration for unit belonging to LAN

auto eth0
iface eth0 inet static
  metric 5 # A positive non-zero constant

The auto-switch feature can be disabled in the daemon’s config file.

An additional feature auto_keepon should help if the LTE network interface is turned off accidentally (e.g. caused by ifdown command). In such a case, the re-enable (UP) operation is performed on that interface and also routing table records are refreshed. The feature is enabled by default and can be disabled in the configuration file.

LED OFF ON Flashing
SIM LTE linux service (daemon) is not active
(disabled or not installed)
SIM is OK Slow — No sim inserted (or SIM corrupted)
Fast — wrong PIN
NET Deregistered from network Registered to network -
SIG No signal Excellent signal Signal quality — faster ∼ better
INT No WAN access Unit online, backup active
(or single interface only)
Slow — connected via the main WAN interface, backup inactive
Fast — connected via backup WAN interface

All LEDs flashing — LTE module is restarting.

  • for optimal signal strength it is necessary to use an external antenna installed in an open space (eg. outside any enclosures). External antenna is included in the package of each LTE controller - during the purchase, you can also choose between the default antenna with magnetic mount, or a larger one with on-wall mount. Both antennas can be also purchased separately
  • Operate both Wi-Fi and LTE simultaneously is not recommended.
  • The Ethernet interface is set as primary while the LTE acts as a backup by default.
  • WAN connection availability is determined by ping to In the config file, the IP can be changed as well as the ping period.