I have a Max Transit (not a DUO). Since there is only one radio in my unit and it can only use one sim at a time what is the function of the “Both SIMS” setting? WAN Connections > Cellular Settings > Sim Card
The modem will try to connect using SIM A. Is it can’t it will try SIM B. If Connected on either SIM A or SIM B and it loses connection it will try the alternate SIM.
With two different network SIMs in your device you have a batter chance of getting and staying connected wherever you go.
Also, you can buy SIMs with a set monthly data allowance. This way you can have two SIMS and burn through the data on one and switch to the next one when the data has run out.