Activating WiFi Calling on your cell phone in order to make and receive calls and text messages in places where your cellular signal is weak or unavailable (e.g. basements or some buildings like the Health Pavilion). This might be especially helpful when logging into Duo via SMS messaging. Each carrier has their own rules for how WiFi Calling will affect your data plan and/or which devices this feature is offered on, so please check your carrier's website for the specific details.