Natural disasters like the hurricanes affecting Florida can easily disrupt cellular networks, preventing people from calling emergency responders or loved ones. If cellular service is down but a nearby Wi-Fi connection is still up, you can use that access to make and receive phone calls.
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Both iPhone and Android phones offer a Wi-Fi calling feature that will allow audio and video calls if cellular service is spotty, weak, or completely down. Here's how this works.
Wi-Fi calling has been available since the iPhone 5c. However, not all carriers support it. To find out if your carrier offers it, browse to Apple's page on "Wireless carrier support and features for iPhone." Select your region and look for your carrier. Check the bullet point items to see if Wi-Fi Calling is listed.
To set up the feature, open the Settings app, select Cellular, and then tap the entry for "Wi-Fi Calling." Turn on the switch for "Wi-Fi Calling on this iPhone" if it's off. A message pops up to tell you what information is sent to your carrier when you activate Wi-Fi Calling. Tap Enable to turn on the feature.
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To help you minimize data costs when you roam beyond your coverage area, some carriers provide an option to use Wi-Fi while roaming. If your carrier supports this, turn on the switch for "Prefer Wi-Fi While Roaming." In this event, phone calls may use Wi-Fi when you're roaming and there's a choice between an available cellular network and a local Wi-Fi network.
Screenshot by Lance WhitneyThe first time you enable Wi-Fi Calling, a screen prompts you to enter your address so that you can make emergency calls. After filling in your address, check the box to agree to the terms and conditions, and then tap Save at the bottom of the screen. Your address is confirmed, and Wi-Fi Calling is enabled.
If you ever change your address and need to update the one you entered here, tap the Update Emergency Address link on the Wi-Fi Calling settings screen and enter your new address details.
Screenshot by Lance WhitneyTo check that Wi-Fi Calling is turned on, look for the words Wi-Fi after your phone's carrier name. You'll see this on the home screen on phones prior to the iPhone X and in Control Center on the iPhone X and later phones.
Screenshot by Lance WhitneyThe next time you need to make an audio or video call, and a cellular connection isn't available, your phone will use the closest Wi-Fi network whether that's at home or elsewhere. When your phone receives a call with no cellular connection available, Wi-Fi Calling will let you answer the call if you're connected to a Wi-Fi network.
Screenshot by Lance WhitneyWi-Fi calling on Android has been available since 2015. In the US, the major carriers -- Verizon, AT&T, and T-Mobile -- offer it. I couldn't find a list of supported carriers as with the iPhone, but you can easily tell if the feature will work with your device and carrier and enable it at the same time.
On a standard Android phone such as a Google Pixel, open the Phone app. Tap the three-dot More icon at the top and select Settings. Tap the entry for Calls. If the Call settings screen displays an option for Wi-Fi calling, then you're in business. Tap that option and turn on the switch for "Wi-Fi Calling" or "Use Wi-Fi Calling."
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Tap the option for Calling preference and you can then choose whether you'd rather use cellular if Wi-Fi is unavailable or Wi-Fi if cellular is unavailable. In this case, you'll want to select Wi-Fi as your preferred choice.
Screenshot by Lance WhitneyOn a Samsung phone, open the Phone app. Tap the three-dot icon and select Settings. Swipe down the Call settings screen and turn on the switch for Wi-Fi calling.
Screenshot by Lance WhitneyTo call someone if cellular service is down or just unreliable, open the Phone app and place the call, either audio or video. After the other person answers, you should see a notice that the call is going through Wi-Fi. On the flip side, any call you receive will be received via your connected Wi-Fi network.
Screenshot by Lance Whitney