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Help Why do I lose internet when I'm on a phone call?

JohnJSal

Android Expert
Jun 17, 2010
952
72
This used to happen with my S4, and now also with my S7. Whenever I get on the phone, I completely lose internet access. The icon in the notification bar disappears and the internet doesn't work.

This didn't used to happen before I moved to a new city, but my data signal here is very strong, so I don't think I'm hovering on the edge of it working or not. I get a full set of bars for cell service, and roughly 30 Mbps download speeed, so everything seems fine. It's just when I get on the phone, the internet is gone.

I THINK when I had VoLTE activated, I did have internet while on the phone, but I deactivated it because I think it's degrading my call quality for the person on the other end of the line. But does this matter? Why should that affect whether I have an LTE signal?

Thanks!
 
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Good catch. I found this out only when my bank wanted to simultaneously text a security code while on a voice call.

Sorry I have no solution.

FYI I've LTE Off, to minimize dropped network signal.

PS many callees tell me my voice is garbled, even though I hear them well.

PS2 I'm also noticing momentary network signal loss upon entering indoors.
 
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If VoLTE (Voice over LTE) is turned off, or isn't supported or not available, the phone has to drop back to CDMA/EVDO modes for the phone calls, and that can't do calls and data simultaneously. And that's why Internet isn't available during phone calls. GSM, HSDPA and TD-SCDMA networks don't have this limitation
 
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GSM, HSDPA and TD-SCDMA networks don't have this limitation
T-Mobile is a GSM network, or else that would have been my thought as well.

I do believe the gist of it is correct, though. If Voice over LTE (VoLTE) is disabled, the handset will have to fall back to 3G to make the call since LTE doesn't support voice calls on its own. The phone would then automatically switch back to LTE after the call is completed, hence the momentary disconnection.

This doesn't explain why the data connection would be nonfunctional while on a call, though. So I'm not sure what's up with that...
 
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If VoLTE (Voice over LTE) is turned off, or isn't supported or not available, the phone has to drop back to CDMA/EVDO modes for the phone calls, and that can't do calls and data simultaneously. And that's why Internet isn't available during phone calls. GSM, HSDPA and TD-SCDMA networks don't have this limitation

I'm on T-Mobile, so that doesn't explain it for me. This wasn't an issue a long time ago, but in the past year or so I've noticed it. I can still get SMS, just not data.
 
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I'm on T-Mobile, so that doesn't explain it for me. This wasn't an issue a long time ago, but in the past year or so I've noticed it. I can still get SMS, just not data.

Possibly something changed. Although I've never used T-Mobile (nor Verizon) of course, I'm in China. :) But I know before I had LTE 4G with V0LTE, that I definitely used to be able to have data and calls with 3G networks, both in the UK and China. When I've been tethering a laptop, I could still make phone calls, without the laptop going off-line. In the last couple of years any LTE capable phones I've had with service, VoLTE is always there, and only way to stop it, is to turn off LTE completely and go to 2G 3G only, but I've had no reason to do that myself, unless there's no LTE service, because I was out in the Inner Mongolian grasslands or something.

Just a guess, but perhaps T-Mobile has decided now because of LTE 4G with VoLTE, that they no longer have to support simultaneous phone calls and data with 3G.
 
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Just to be specific, I'm on T-Mobile and I get a strong 4G LTE signal (with the icon in the notification bar). So it isn't that I'm only on a 3G connection, because I know you can't do simultaneous phone and data with that.

But even with my LTE connection, it drops immediately (and the icon disappears) when I'm on a phone call. It comes back right after the call ends.

Isn't the call using the 3G network? Why would that affect the data connection?
 
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