The Problematic So-called "3G Going Away" Campaign

For example, if one uses an LTE device by a non-mainstream foreign manufacturer who is not on the list of "will still work" (.PDF by AT&T; https://www.att.com/idpassets/images/support/wireless/Devices-Working-on-ATT-Network.pdf), then would AT&T just block it out of the network?

Yes they will and in fact have already started doing this. Phones not on the list will no longer be activated and customers who regularly swap their SIM cards between supported and non supported phones have had their service suspended. You do raise an interesting question about foreigner’s roaming on ATT’s network. I have no idea what happens to them.

@nanjingk010 

The discontinuance of AT&T's 3G network has been publically known for a long time. The termination is set for Feb. 2022 but may be sooner with certain devices. AT&T will continue to support the newer technologies like 4G/LTE/5G etc.

The IMEI number is the registration number for AT&T and is also used to track the phone or to blocking the phone.

The IMSI number is sent by the phone to the current network while registering to allow the network hardware to recognize the phone. AT&T, like other carriers, have a specific code which is converted into a phone number that is recognized by the MCC, MNC, and MSIN codes of the carrier. The IMSI is either stored on the SIM card or hard coded into the phone. So, with the IMSI number, AT&T can tell what the phone is and whether it will work on their network or not. IMSI is why hacked phones or phones not intended for the U.S. domestic market sometimes don't work.

@sandblaster 

(don't know how to quote, so tried at-ing here) 

Thank you for your prompt and informational reply and appreciation in regards to the point about foreign devices. 

To clarify, when mentioning devices not on the list, I meant those already activated (not new) and 4G/LTE-capable (for example, a foreign device or a non-mainstream/boutique device, or a testing device). Would those just being blocked out by the network? 

In addition, tied to your information on another post about iPhone 5/5s whose voice communication is not exclusively LTE (showing 4G for data when calling) - it is also questionable about 4G-non-LTE devices - would those be supported at all? They would not be mainstream (here in the US), but still exist as particular versions (by main or regional networks) or in the foreigner-device bucket. 

Relevantly, it is also important that there is a known and high enough frequency with which AT&T updates this list going forward, so that it extends towards comprehensiveness with respect to new devices that are being designed and manufactured in the future, for this is hardly mentioned by AT&T with the web page and the linked .PDF document. 

Further enquiries, when made to customer service line, are not rendering much helpful yet rather more confusing understanding of this issue, as representatives imply manufacturers (although not innocent) to be the ultimate culprit for this move. 

Just hope the network changing issue can be a more solid move with ongoing attention.

Note: without intention to bombard the community, I posted at multiple sections because the main issue has separate relevancy in its sub-issues to different sections (E.g. the main issue of 3G/4G/LTE is about Network Coverage, the issue about off-list devices is related to Device Features, and the absence of customer service support for promotions towards prepaid device upgrades is related to Prepaid or Device Upgrades). 

Look it all has to do with VoLTE.  Att has a whitelist and if the model of phone is not on it then guess what it won't work period.  

To clarify, when mentioning devices not on the list, I meant those already activated (not new) and 4G/LTE-capable (for example, a foreign device or a non-mainstream/boutique device, or a testing device). Would those just being blocked out by the network? 

No. Non supported devices already active will continue to work until the shutdown. My son has a non supported phone still and will need to upgrade but his phone should continue to work until the shutdown date.

In addition, tied to your information on another post about iPhone 5/5s whose voice communication is not exclusively LTE (showing 4G for data when calling) - it is also questionable about 4G-non-LTE devices - would those be supported at all?

No. Only iPhone 6 and newer are supported. As noted above, the issue isn’t LTE capable phone’s, it’s VoLTE capable and certified.

I'm going to disagree slightly with sandblasters reply.

To clarify, when mentioning devices not on the list, I meant those already activated (not new)

Older at&t phones have all compatible bands, but not HD voice.  Most will remain just fine until 3g shuts down.

and 4G/LTE-capable (for example, a foreign device or a non-mainstream/boutique device, or a testing device). Would those just being blocked out by the network? 

Not as easy to say yes with non at&t phones.  It depends on the device specifications. 

    Many are lacking LTE bands for data and HSPA bands for 3g.  There have already been posts I've read and responded to, where voice service is spotty, garbled, or out.  This is because at&t has 2 HSPA bands, and one is being repurposed already for 5g.  If that band is the only HSPA band in common, you lose voice.  

    Cover your bases.

I just had to call AT&T to have my device turned back on for the third time in 6 months. My device is 5g compatible so it should not be getting these service suspensions due to 3g going away. In addition this crap is not supposed to occur until February.  I am at the point of charging AT&T for missed business calls when this occurs. Does the FCC know they are suspending service of customers to notify them of this 3g going away thing that wont happen for at least 3 more months? 

@WiseA Feb. 2022 is the date for the complete shutdown of the 3G service, but it's not going to be all at once. There are service areas that have already begun the process and AT&T has stopped allowing new 3G devices to be registered. If you have a registered 3G device with AT&T you should have received a notice and an offer for a free comparable phone that won't be affected by the shutdown. Admittedly the free replacements are barely adequate but they will get you thru the shutdown until you can upgrade to a compatible phone of your choosing.

@WiseA

I just had to call AT&T to have my device turned back on for the third time in 6 months.

If it's being turned off, then it's either not compatible, or AT&T's system does not see it as compatible.   Which is it?  

My device is 5g compatible so it should not be getting these service suspensions due to 3g going away.

According to AT&T?  Is it on the unlocked list?  Does it use LTE for voice calls?   Or are you just going by what the specs are, and figuring it should work?   But AT&T says no? 

In addition this crap is not supposed to occur until February. 

Or sooner?  At&t can't shut off the entire USA 3g in 28 days.  It's a gradual shut down. 

I am at the point of charging AT&T for missed business calls when this occurs.

You don't think 6 months of shut offs (hints) that your phone can't work on at&t isn't enough for them to say, "you had notice"?    

Does the FCC know they are suspending service of customers to notify them of this 3g going away thing that wont happen for at least 3 more months?

The FCC not only knows, it's published on their website, and they are the ones who will fine At&t for not having all e911 compliant phones.