I have a dual-sim (RM-1096) but haven't tried using two at the same time, so please take my answers with a grain of salt, these are assumptions, maybe someone with two-active can verify for a certainty. When you say "can you receive call on both at once", if you mean can you insert two active sim cards, and have calls go to either sim/number, yes, that is the point of dual-sim, and the UI allows for this by having a dedicated SIM 1 phone tile and a SIM 2 phone tile. Can you turn off SIM cards after they're inserted? Yes. Under Settings --> cellular+SIM, there is one setting for "SIM 1 settings" and one for "SIM 2 settings", which include "SIM status" on/off.
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