For the LTE Samsung smart watches to receive calls and messages without a phone, mobile data service must be activated for the watch first.
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How to set up eSim in Samsung Galaxy Watch 5 LTE , Watch 5 Pro , Watch 4 LTE
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Samsung Galaxy Watch - Activate / Set Up Device
How to Set Up Your Samsung Galaxy Watch 4
Get your Samsung smart watch's information
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Problems with call and text messages on your Samsung smart watch
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