When using a GX with 4G modem and a Modbus connection on ethernet, the GSM connection does not automatically connect. Even after removing the ethernet gateway the only way to get the GSM to connect is to briefly unplug/replug the ethernet and then the GSM will connect for about 15min. This is clearly not a solution for an unattended remote site.
Hi Trevor,
No solution to your problem, but some information to one question in the post you linked:
connman is a unix utility: connection manager.
this is an alternative to wpa-supplicant.
so if you see a configuration file with the comment: #changed by connman
for example, this means that the config file has been updated by the external utility.
Hope this helps clarify this issue.
BTW, we use a TP link 4G LTE modem to supply the network at our location, and have no issues with the Cerbo staying connected. One of the modem settings will disconnect from the network if there is no traffic after a set time period - I have disabled this so we are always connected, even if there is no traffic.