Even while connected to the watch? I know the original Gear could only do that if it was a carrier version. I mean, it was a ATT watch and I use Verizon but it didn't matter because I wasn't adding it directly to my plan.
I'm not sure of what you're asking, but a watch that doesn't have a SIM card in it (which would be adding it to your plan - the ST&T watch was probably on an AT&T plan) can't make or take calls (or texts) without being connected to a phone.
My S3 is not carrier branded and does not have a sim slot, but I can talk to and hear calls, from the watch itself, as long as it is connected via BT, to my phone.
Ok, just checking, I wasn't sure how that function evolved through the watch generations. the Gear S for instance, the generic non-carrier versions couldn't take or recieve calls even when connected to the watch as I understood.