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New Member

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4 Messages

Wed, Oct 20, 2021 6:45 PM

HD Voice Compatibility With Samsung Galaxy S20 FE (SM-G780G)

I have a Samsung Galaxy S20 FE (SM-G780G) that appears to support HD Voice, but AT&T's database says that it doesn't, and thus service to the phone/SIM keeps getting disabled. I have performed testing and found that the phone appears to support LTE calling, even with AT&T service. During the the following tests I use an AT&T prepaid SIM card and an AT&T postpaid SIM card that my work pays for through their account.

Test 1 - SM-G780G with prepaid SIM card, Galaxy S10e with postpaid SIM card : SM-G780G shows H+ during a call. Galaxy S10e shows LTE during the call.

Test 2 - SM-G780G with postpaid SIM card, Galaxy S10e with prepaid SIM card: SM-G780G shows LTE during call, S10e shows LTE during call. SM-G780G received a text message saying that the phone is not compatible, but was still able to place an LTE call.

Test 3 - SM-G780G with prepaid SIM card, Galaxy S10e with postpaid SIM card: SM-G780G shows LTE during call.

Test 4 (roughly 5 minutes after Test 3) - SM-G780G with prepaid SIM card, calling a third phone number now: SM-G780G shows H+ during the call.

Test 5 (roughly 5 minutes after Test 4) - SM-G780G/prepaid SIM card is now disabled and calls go directly to AT&T support.

It appears to me that the phone fully supports HD Voice, but that AT&T has it incorrectly labelled as non-HD Voice compatible. Am I able to work with AT&T to allow the phone to place HD Voice calls, seeing as my tests show that the phone is capable? Am I able to mark the SIM card/phone as HD Voice compatible (like an override), and then if calls don't work after 3G is shut down (even though my tests show that it supports HD Voice), then that just becomes a problem for me to resolve at that time?

Accepted Solution

Official Solution

sandblaster

ACE - Expert

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55.4K Messages

3 m ago

Is the phone on ATT’s supported phone list? Without looking at the list, my guess is it isn’t on the

list. If not, then it is not supported for VoLTE by ATT even if it is VoLTE capable. There are many phones capable of VoLTE that are not on ATT’s list and therefore not supported. The reason any phone is not on the list is the manufacturer did not submit it for ATT’s certification tests.

JefferMC

ACE - Expert

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26.6K Messages

3 m ago

If the phone isn't on AT&T's lists, then AT&T doesn't support it.  If this bothers you, I refer you to this video explaining their position about that:

https://vimeo.com/355556831

New Member

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4 Messages

3 m ago

Sandblaster, you are right, the exact model is not in the supported list. Thank you for your informative answer. Is there any sort of override that I can apply to the SIM card to let it work anyways? Is there some sort of security reason for not allowing phones that support VoLTE but aren't in the supported phone list to place VoLTE calls anyways? It seems ridiculous that AT&T won't allow the phone to make VoLTE calls while just not guaranteeing the functionality.

sandblaster

ACE - Expert

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55.4K Messages

3 m ago

There is no override. As for the reason this or any other VoLTE capable phone is not supported, your guess is as good as mine but I doubt it has anything to do with security. One theory is simply too many support calls and it’s easier to disallow altogether than not guarantee functionality. 

New Member

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3 Messages

10 d ago

Same issue! My phone is fully capable but every service provider says it isn't. I have a button to turn voLTE on and off....but the system says my phone can't support it. 

New Member

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4 Messages

10 d ago

@frodo_saint we ended up just leaving AT&T in favor of T-mobile since we already bought the phone. We just put the T-Mobile sim card in, rebooted the phone, and the VoLTE works flawlessly. Still mad at AT&T for doing this. The phone would work great on AT&T if they would just let it.

ACE - Sage

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92.1K Messages

10 d ago

@frodo_saint

Just because your phone has a 'voice over LTE switch' does not mean that is actually capable of doing so on at&t. 

T mobile has an imei check here

https://www.t-mobile.com/resources/bring-your-own-phone#imeiextender

New Member

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3 Messages

10 d ago

@formerlyknownas  it's a Samsung s20 FE. It is capable and is sold on their website. I didn't get mine through them as I had a different provider at the time, and always just buy unlocked phones. 

@igotahar0 at&ts online support is currently trying to get mine to update in their system. If they aren't able to I'll try t-mobile. I just want a phone that works without all the hassle 

ACE - Sage

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92.1K Messages

10 d ago

@frodo_saint

That still tells me nothing.

Are you saying this phone boots with an AT&T blue globe? Or is this a different model meant for another country? Or another carrier?

These model are whitelisted 

Galaxy S20 FE (G781W, G781B, G781B/DS, G780F, G780F/DS)

If yours isn't listed, you can't use it on at&t

New Member

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4 Messages

10 d ago

While I am not frodo_saint, it sounds like frodo_saint has the same phone that I have - the SM-G780G. Seeing as the phone VoLTE works great on t-mobile, -and- with sim swapping we can finesse AT&T into allowing the phone to work (see test 3 in my OP), it seems that the phone is fully capable, and AT&T for whatever reason just blocks it.

ACE - Sage

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92.1K Messages

10 d ago

@igotahar0

Samsung has to submit for testing.  As you can see, several non US models were tested and added to the list.  The G model either wasn't, or won't. 

New Member

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3 Messages

10 d ago

@formerlyknownas   It's the g780f. Whatever reason when they key in my IMEI number it comes up in their system as not compatible. They are trying to fix the issue and update it. Idk if they will be able to or not, but I'm grateful they're at least trying. My previous company said my phone wasn't capable and just pushed selling me a new phone. 

ACE - Sage

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92.1K Messages

10 d ago

The IMEI determines how its identified as model 'F' or 'G'.   

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