Help me understand Wi-Fi Calling, since tech support can't...
January 4, 2022 8:41 AM   Subscribe

My iPhone (x) is on AT&T but we live in an area with very shoddy reception (AT&T is among the best but still very bad). I have Wi-Fi calling but my calls still fail all the time. Does that make sense, or does it mean that Wi-Fi calling isn't working? When I look at my phone, it shows that Wi-Fi calling is on, I have a strong Wi-Fi connection (internet works great), but I have no bars and calls fail (as do regular green-bubble SMS text messages). Should that be happening?
posted by malhouse to Computers & Internet (10 answers total) 1 user marked this as a favorite
Two things:

1.) Try and disable your Cellular service and just leave the wifi on. Best way to do that: Turn on Airplane Mode and then go turn on WiFi and make sure it's connected.

2.) Turn off Wi-Fi calling, reboot the phone, and turn it back on. There may be some registration piece that didn't take on the AT&T side, especially if you're doing it somewhere with crap reception.
posted by deezil at 8:49 AM on January 4, 2022 [3 favorites]

I've never had wifi calling work well with my iphone. If I'm using wifi, I use facetime audio or facebook messenger. Otherwise, I try normal phone calls. In my experience, Wifi calling does poorly at handing it off to wifi / vice versa, so I leave the setting off.

My guess is that your phone tries to use traditional calling, with wifi calling as a backup. It never switches to wifi. You could try to test the theory by turning on airplane mode, but then connecting to wifi and try a traditional call and see if that improves things. But for me and mine, we use facetime/facebook messenger.
posted by bbqturtle at 8:50 AM on January 4, 2022

You might try shutting off the cellular antenna and going wifi only. On the iphone, you would do that by turning off the "radio tower" looking antenna thing in the control center. You would leave WiFi on. (I.e., like you are using WiFi on a plane, with cellular shut off).

It is possible your phone is switching between cellular and WiFi and dropping the calls in the hand-off. I have seen my phone do this in areas with poor cellular coverage but OK WiFi.
posted by Mid at 8:50 AM on January 4, 2022

Response by poster: Okay this is working. It's too bad that I have to remember that extra step when I enter or leave the house, but it's better than the status quo... awesome! Thank you!
posted by malhouse at 8:58 AM on January 4, 2022

Just another data point saying that I have to do this, too--to use only WiFi for calls, I have to go data mode, otherwise it keeps trying to use the cell service first, and WiFi as backup. I'm on an iphone but a different service provider.
posted by assenav at 9:10 AM on January 4, 2022

I have found that restarting my phone often makes Wi-Fi calling work again.
posted by Grandysaur at 9:33 AM on January 4, 2022

The actual guts of Wifi calling involves a persistent IPSEC connection. Your phone makes a UDP connection on port 500 to your service provider and then a longer connection on UDP port 4500 and uses keep alive to keep these up. When the keep alive on 4500 fails a lot of times your phone just drops back to cellular. If your local IP changes, it will invalidate these and make the keep alive fail.

Most consumer Wifi routers are pretty lenient on outbound connections like this and it should work alright. If you have a mesh system or anything a little more complicated, it can cause issues.
posted by cmm at 9:44 AM on January 4, 2022 [2 favorites]

Response by poster: Ah we have a mesh system (eero)
posted by malhouse at 10:29 AM on January 4, 2022

If you're talking with friends who could be convinced to install software, I've found a whatsapp voice call is far more forgiving of bad networks than my phone's phone software. That obviously doesn't help with incoming calls or business calls.
posted by eotvos at 12:58 PM on January 4, 2022

Slightly off-topic. As someone who's best worst carrier option in a rural area is AT&T consider switching to Cricket Wireless. They are a subsidiary of AT&T, you use the same network, but you get significantly better pricing. I hated paying AT&T's city rates when I got so much less in the way of service from them.
posted by Hey, Zeus! at 2:20 PM on January 4, 2022

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