I don't think it's equivalent judging by the fact that you can still make emergency calls, which means it's able to talk to the network anyway. I remember than

I don't think it's equivalent judging by the fact that you can still make emergency calls, which means it's able to talk to the network anyway. I remember than an older Samsung I had (GS3 IIRC) would show the signal level even withou a SIM installed. Don't know what happens when you put it in airplane mode, though.