Mobile Carriers in the United States

[Lt. Dillinger]

It's possible that different accounts have different RF band permission.  For instance, an AT&T unlimited plan might work different than a "pay as you go" plan or various plans with AT&T network MVNOs.

So you pretty much have to try out each plan on each service to know if it's going to work.

I don't have a PinePhone, but I've done the "bring your own device" thing on discount MVNOs about a dozen times over the years.  So I've run into these "gotchas" a lot.  Sometimes it's possible to find the actual technical restrictions of a given plan, sometimes it is not.

These appear to be the bands the PinePhone will work on:

Code:

LTE: B1, B2, B3, B4, B5, B7, B8, B12, B13, B18, B19, B20, B25, B26, B28, B38, B39, B40, B41
WCDMA: B1, B2, B4, B5, B6, B8, B19
GSM: 850, 900, 1800, 1900 (MHz)

Are there current software restrictions on this?
At least you can mostly eliminate some plans just knowing this.

I am not sure I fully understand what you are saying.
In your example, AT&T has different plans, but they should all use the same network, or not?
I thought the phone networks were dependent on the carrier (Verizon, AT&T, etc).
Are you saying that knowing the carrier is not enough to know if it is going to work or not?
Same question but from another angle. Can AT&T (or any other carrier) change network type depending on the plan?

Can you please clarify on this?

What he's trying to say is that some devices are limited to which bands they can access. It is not based on plan, but on device. For instance, when t-mobile took over sprint they bricked band 41 for all but new 5g devices because spectrum sharing has not worked out yet.

What they can do is prioritize traffic based on plan (by apn) which can slow your speeds. But if your modem is capable, you will get access to the band unless they have a specific whitelist of block device imei's that are allowed or not - which verizon and AT&T do. In those cases, network access is blocked by device imei, not by plan. Usually this is done because a device does not meet the carriers access requirements, such as all the devices that are about to get kicked off because of no VoLTE support. The pinephone does have support for VoLTE, but whitelisting may still be an issue. T-mobile does not use whitelists.

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When you say "not finding their cell towers at all" do you mean you have no bars? If you have no bars, then obviously you won't be able to connect. Maybe you should pop another OS onto a sim card and boot from it just to make sure your hardware is ok. There is for instance the factory test image in the postmarket demo builds. It only tests hardware. July 20 something is the date on it.

No bars because it won't connect to any cell towers.  My wife works fine, bluetooth too, but it's hit and miss on finding the SIM card too.  Sometimes I reboot and it finds the SOM card, other times not.  I've got a buddy close to me who's a cell phone guru and I'm gonna let him have a look.  We've been talking about this phone, so he's a bit interested in it too.

The issue could be the OS, I have tried the factory image of the Postmarket os image and it shows the modem is working but when using UBports it does not work with my T-mobile sim. Another thing is I've heard about the firmware for the modem being corrupted in some cases. Have you tried another os such as Mobian to see if it will work with your SIM card?

No I haven't as I really want to stick with Ubuntu Touch OS.  I'm hoping that with updates many of these issues will be worked out.  What I find interesting is the tech at Mint Mobile said she was able to help some users get their phones working.  So I guess it is a hit and miss, phone by phone situation which I find intriguing.  It's kind of like the squeak you hear in your car, it's there daily but the day you take it to the dealership, it's gone.  

This might sound silly but have you tried taking the phone somewhere else and seeing if it can access Mint? In your other post, your phone clearly sees a band 13 tower which is verizon based. You simply may not have a t-mobile tower close enough for the pinephone to access.

Yes, I was in two different areas today and still no connection.  Also, according to the Mint Mobile website, where I live the map shows very good coverage.  I've got to take my wife's iPhone in for a screen repair and I'm going to ask the folks there for some suggestion.  Maybe that can help, maybe no.