At-home systems use a base station plugged into a landline or connected over cellular, paired with a wearable help button (pendant or wristband) that works within a set range of the base — typically throughout a house and yard, not beyond it.
Mobile GPS systems are a separate small device, worn or carried, that use cellular and GPS so they work anywhere there's signal — running errands, at the grocery store, on a walk. They generally cost more and need charging, unlike most at-home base stations.
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