WiFi calling unreliable. According to Swisscom Support not supported in flight mode.

I have WiFi in my office and at home. The network reception (GSM/VoLTE) is poor in both locations.

So I got into the habit of turning on airplane mode and turning on WiFi. I can make and receive calls via WiFi calling. The only problem is: I receive calls very unreliably.

Yesterday I received 4 missed calls while WiFi calling was active in airplane mode.
When I turned off flight mode in the evening, I received 4 text messages from Swisscom about missed calls.

So I called Swisscom support today. The answer was:
“Wifi calling is not supported in airplane mode. Network reception must be possible, i.e. airplane mode must be off.”

This statement contradicts that on swisscom.ch:
“When Wi-Fi Calling is turned on, you can make and receive voice calls over a Wi-Fi network when network reception is weak or nonexistent.”(https://www.highly.co /hl/WZ54sEq9cPOrDI)¨¨)

“Not at all” is pretty much the same as when I’m in airplane mode. Of course the GSM unit is switched off in airplane mode, but the result is the same: no network reception.

I wanted to know exactly and called Apple. Apple confirmed my suspicion that WiFi calling should also be supported in airplane mode.

So it’s not acceptable for Swisscom to inform me incorrectly and thus quickly sweep a problem under the carpet.

Professional support looks different!

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  • WalterB has responded to this post.

    cmyk

    So none of the iPhone devices in my area properly support WiFi calling with active flight mode, the mobile function is inactive in flight mode and how is WiFi calling supposed to work if it depends on mobile mode?

    Check whether “Wi-Fi calling on iPhone” is active under Phone even when airplane mode is activated?

    IMG_1096.PNG

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    Installationen, Netzwerk, Internet, Computertechnik, OS Windows, Apple und Linux.

    • cmyk has responded to this post.

        WalterB

        My post already mentioned that I can make WiFi calls. In airplane mode, WiFi can be turned on and calls can be made and received. Apple has officially confirmed this to me.

        Here’s another screenshot as “proof”:

        wificalling-airplanemode.jpg

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        • WalterB has responded to this post.

            cmyk

            As mentioned, it doesn’t work reliably in airplane mode because my picture on the “phone” is under WiFi calls when airplane mode is active?

            N.B. For me too it sometimes works in flight mode but not reliably, see picture. It may be that the error lies with this telephone function with the “Wi-Fi calls” when flight mode is activated.

            IMG_1097.PNG

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            Installationen, Netzwerk, Internet, Computertechnik, OS Windows, Apple und Linux.

              @WalterB Do you realize that “Mobile Data” (my phone is in English) is not selectable in Airplane Mode? So I can’t check what WiFi Calling says in Airplane Mode.

              Back to my concern: WiFi calling should also work in airplane mode with WiFi activated. This is completely normal SIP/IMS calling and not VoLTE.

              It should be possible to use WiFi calling in airplane mode – as Apple confirmed to me. And reliably.

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              @POGO 1104

              Because I don’t want 10x higher SAR values. And because the battery lasts considerably longer in airplane mode with WiFi.

              SAR value of mobile network approx.: >1.0
              SAR value of WiFI: 0.1–0.3

              [Fact sheet - Mobile phones & smartphones - Federal Office of Health…](https://www.google.ch/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0ahUKEwjElrDertLYAhWBKsAKHbTsBgMQFghcMAY&url=https%3A%2F%2Fwww.bag.admin.ch%2Fdam% 2Fb ag%2Fde%2Fdocuments%2Fstr%2Fnis%2Ffaktenblaetter-emf%2Ffaktenblatt-smartphone.pdf.download.pdf%2Ffaktenblatt%2520smartphone%2520d.pdf&usg=AOvVaw188b_iDbqi4WSui-Z10CqE)

              But it’s about: Why doesn’t what is advertised just work?

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              @cmyk

              The problem with the whole thing will be what’s wrong with switching flight mode to WiFi calling, is it a Swisscom or Apple problem.

              At Swisscom itself there is no indication that it should also work without problems in flight mode. I and others had tried that before and then left it alone with flight mode.

              Support’s claim that it doesn’t work would have to be officially confirmed somehow.

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              Installationen, Netzwerk, Internet, Computertechnik, OS Windows, Apple und Linux.

              @cmyk wrote:

              […]

              But it’s about: Why doesn’t what is advertised just work?

              Well, you can, may and should be critical of advertising claims. But even with the best attempt at interpretation, I don’t see any promise in the Swisscom sales brochures that your unusual solution approach would be supported or even recommended. Maybe it’s the cell phone. Just leave airplane mode off, plug your phone into the charging cable and you’re good. Most people do this and it works perfectly.

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              Have you tried turning it off and on again?

              @cmyk wrote:

              Because I don’t want 10x higher SAR values. And because the battery lasts considerably longer in airplane mode with WiFi.

              SAR value of mobile network approx.: >1.0
              SAR value of WiFI: 0.1–0.3

              The home WLAN generally does not have adaptive transmission power control (TPC):

              https://de.wikipedia.org/wiki/Transmitter_Power_Control

              WiFi with working TPC is very, very rare.

              The modern mobile network (UMTS/3G or LTE/4G) has a fast and well-functioning adaptive transmission power control (TPC).

              Because of the lack of TPC, the mobile phone’s WLAN module always transmits with the maximum transmission power (depending on the amount of data being transferred and the maximum transmission power of the WLAN module, the average transmission power is up to 200 mW = 0.200 W). With an RTP data stream (language G.711) of around 100 kbit/s, this results in an average transmission power of roughly: 0.200 W * 100 kbit/s / 300 MBit/s = 66 μW = 0.000066 W

              The mobile phone only transmits with the minimum necessary transmission power (TX-RSSI measured with a network monitor in the apartment with the window closed: -10 => average transmission power: 100 μW=> 0.000100 W).

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              2 years later

              I would like to record this again.
              WiFi telephony in airplane mode works perfectly outside. Reception absolutely ok. I also receive a call every now and then in this condition. But at least every second call doesn’t make it to me. Gets blocked somewhere along the way.
              Why airplane mode? Because it then opens the poor 4G connection without flight mode and cracks and rattles and is just annoying.
              Is there a way for ALL incoming calls to go through with airplane mode and WiFi telephony?

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              Hello @Diofrakeu74

              The problem is most likely in your home network.

              Because you can always make a call.

              But you’re having problems getting the calls in…

              A special port is required on the network for this.

              This reports that you are now on the WiFi at this location, and so the system knows where to connect the call.

              When the cell phone goes into sleep mode, the system is no longer where you are.

              We had a Cisco AP installed in our 4UG office and the calls always worked there.

              What kind of WiFi AP do you use?

              Greetings Lorenz

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              With VoWLAN (WiFi Calling) a VPN tunnel implemented with IKEv2/IPSec is used. For details see:

              [https://community.swisscom.ch/t5/Mobile/Advanced-Calling-VoLTE-und-WiFi-Calling/m-p/533122/highlight/true#M4663] (https://community.swisscom.ch/t5/Mobile/Advanced-Calling-VoLTE-und-WiFi-Calling/m-p/533122/highlight/true#M4663)

              For NAT devices between the home network/company network and the Internet, NAT traversal (NAT-T) is used for the VPN tunnel required for VoWLAN. If the outgoing calls work fine and the incoming calls don’t go through at all or only partially go through, this smells like a UDP aging problem. See:

              [https://www.lancom-forum.de/viewtopic.php?f=31&t=17621&p=99943&hilit=udp+aging#p99943](https://www.lancom-forum.de/viewtopic.php?f= 31&t=17621&p=99943&hilit=udp+aging#p99943)

              [https://www.lancom-forum.de/viewtopic.php?f=14&t=17510&p=99340&hilit=udp+aging#p99340](https://www.lancom-forum.de/viewtopic.php?f= 14&t=17510&p=99340&hilit=udp+aging#p99340)

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              8 months later

              I’m also looking for a solution and have a suspicion. My provider is UPC, which used to be on the Salt network and is now also on Swisscom. Salt supports WiFi calling worldwide and the other providers only in Switzerland. WiFI calling works without any problems with Salt and hasn’t worked with UPC/Swisscom for a few weeks now. So it’s not the WLAN or Apple, but rather the Swisscom, who want to check whether you are in Switzerland. There is the option of IP address, GPS or cell information. A VPN connection to Switzerland doesn’t help, the IP address probably won’t be there. Swisscom could still query the networks if Apple helps, but this is only possible in flight mode. That leaves GPS and/or the surrounding WiFi networks and Apple would have to help there too. This is the most likely variant, that Apple will determine the location and inform Swisscom. In airplane mode it will also be difficult for Apple if only its own WLAN is available. No provider has yet explained where the location comes from. The reason will be that you can earn very well with roaming… The only solution is WiFi calling from Salt, which works worldwide and there is also a need for help if WiFi calling fails and doesn’t come back on its own. The other providers are looking for excuses because Salt is proof that it works and Apple is right because it is technically possible, only the providers sometimes block the conversations according to their own taste.

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              Another addition that Apple is playing along: there is a “Wi-Fi calling” switch under Settings, Data Protection, System Services. Apple determines the location for Swisscom and, probably if the information is insufficient, Swisscom then rejects the calls. In airplane mode, Apple has more trouble determining your location. That would also explain why VPN doesn’t help abroad. The agreements between Apple and the providers likely require Apple not to use WiFi calling if the provider only allows national WiFi connections and the location is not precise. With Salt you can also use a hot spot (second cell phone).

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