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[Q] What US Carrier is the International GTab 7.0 plus (P6200) fully compatible with?

Sorry for what is probably a stupid question.
I am thinking of buying an International version of the 7.0 plus (P6200) but I'm having a hard time figuring out which US Carrier, if any, (AT&T, T-Moble or Verizon) is fully compatible with the table's supported frequencies.
Any help in pointing me to the carrier, that will allow the tablet to get 3g data and allow the tablet to make phone calls, would be greatly appreciated.
Also, if you are using a P6200 in the US, I would be interested in what carrier you use, your opinions of the carrier and your opinion of the tablet in general.
Thank you

Over 140 views but no replies.
Does no one know the answer or is the question so simple it is basic knowledge I should already know?

I'm not familar witht eh international model but I can tell you that it won't work with Sprint or Verizon as they are CDMA and not GSM. So that leaves T-Mobile and AT&T and it would depend upon what frequency the GTab7+ recieves, is it tri-band (850, 1800, 1900) or just a single band? AT&T uses 850/1900 MHz and T-Moblile 1900 MHz for 3G service. I would assume that it would be tri-band as are so called "world phones".

TMo also requires UMTS1700.
So almost surely it will NOT get 3G service on TMo. That's why there is a special Tmo variant.
Don't know about AT&T

Thank you for your reply!
Here are the listed frequencies for the tablet
2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 900 / 1900 / 2100
it appears that it supports all the frequencies for AT&T and T-Mobile. I guess my confusion is I can't tell if the tablet will support 3G or just 2G (wouldn't be worth it if all I could get is 2G).

Entropy512 said:
TMo also requires UMTS1700.
So almost surely it will NOT get 3G service on TMo. That's why there is a special Tmo variant.
Don't know about AT&T
Click to expand...
Click to collapse
Ahh, that is what I was looking for. As much as I dislike them, seems I will need to go with AT&T if I get this tablet.
Thank you very much, both of you!

Sorry I got a little confused between tabs and phones. Verizon uses EV-DO (CDMA based) for 3G and AT&T is HSDPA (GSM based) at 1900 MHz. T-Mobile uses 1700 and 2100 MHz for 3G.

warning, if you plan on using as phone and tab, at&t may want to make sure you are on tab data plan as well an it could be pricey for both.
with that being said Im using this on att with voice and unlimited grandfathered smartphone data. havent heard a word from them. I pray it stays this way. I will fight them for it.
conclusion: best mobile device in the world right now IMHO, until 7.7 comes out.

P6200 and iPhone SIM
Hi all,
just to make sure...
If I get the P6200, can I just pop my iPhone 3gs SIM with unlimited data plan (as long as I don't use it too much)?
I saw someone said they can do that on the 7.7 thread but I wanted to make sure the AT&T iPhone SIM isn't restricted to iPhones somehow.
Thanks
O

I have GT-P620900 from the Philippines and I am my tablet in the US now. I tested using at&t sim card and it works when I tried making a call using sim card (gsm).
Sent from my GT-P6200 using Tapatalk

Hi Neogrin,
With the posted frequencies:
2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 900 / 1900 / 2100
it will work perfectly for 3G (HSDPA/HSPA+) speeds only on AT&T. You should get 2-4 Mbps downlink, or maybe even more with a good signal on AT&T.
Unfortunately for T-Mobile (whom I also prefer over AT&T), it will only work on their 2G network, at EDGE speeds, which would be about 200 Kbps if you are lucky. Actually, EDGE speeds are good enough for twitter, facebook, and a bit of surfing, but would be frustratingly slow for YouTube or downloading apps.
The Tab 7plus will NOT work on Sprint or Verizon as their CDMA, LTE, and WiMax networks are different technology from GSM and HSDPA and thus not compatible.
Internationally, the 7plus should work on almost any 2G or 3G network, with maybe a few country exceptions here and there.
BTW if you decide to activate your 7plus on AT&T, I can share a bit of experience. I received a Tab 7.7 3G this week, with a similar frequency list to the 7plus. (Unfortunately, it also lacks the "AWS" 1700/2100 band for T-Mobile). I went to an AT&T store today to activate the 7.7 on a month-to-month data plan, of US$25 for 2GB with US$10 per each 1GB of overage. They were not able to assign the data plan in their system to me, because the 7.7 3G is not an AT&T device. The same will be true for your 7plus. What they did to get it to work was to take the IMEI number from one of the other tablets they had on display in the store - making sure it was an HSDPA tablet, and not an LTE one - and used that to activate my account. It took them a while to figure this out, but when they did, it worked. Once the account was activated, and the SIM card was in my 7.7, it found AT&T service and I immediately got a welcome text message. However, data did not yet work - for that I had to do one more thing, which the staff did not know about (but luckily I did).
Go into Settings->Wireless and Networks->Mobile Network Settings
In there is an "Access Point Names" item.
Click on this, and you should see some entries. If it's a new AT&T SIM, it likely says "Cingular 410" or "wap.cingular" or something. This would be correct for a phone, but does not work with tablet data plans, so we need to add the correct one.
Bring up the menu, and there should be a "New APN" option. Select this. In the form which comes up, in the "Name" field, enter "broadband" (one word, no caps, without the quotes). In the "APN" field, do the same - "broadband" one word, no caps, no quotes.
Once you've done this, hit the menu again, and there should be a "Save" option. Choose this, and it will take you back to the list of APNs. Now in the list there should be an APN item called "broadband" which you just created. Press the radio button to the far right of the broadband item. It should turn green.
Give the tablet a few seconds, or a minute, and data should start working!
Hope this helps.
Craig

[Q] Motorola RAZR HD XT925 LTE Frequencies

Hey Guys,
I have a Motorola RAZR HD XT925 which was sourced from Rogers Canada. I was wondering how I can check the devices LTE frequencies? Is there any engineering code and/or menu that would assist with this? This device apparently supports LTE 800 / 1800 / 2600 or LTE 700 / 800 / 1700 / 1800 / 2600 according to GSM Arena. I am wanting to use the LTE 1800MHz frequency in Australia, though cannot get it to connect.
I have tried the following:
Searching for networks manually / letting the device select them automatically
Toggling between 3G only and Automatic (4G/3G/2G)
I definitely have the correct APN settings configured (for Telstra in Australia)
Data is enabled, the SIM card connects to 4G in another mobile
Any assistance would be appreciated, in finding out which LTE network frequencies this device supports.

MarrkDaviid said:
Hey Guys,
I have a Motorola RAZR HD XT925 which was sourced from Rogers Canada. I was wondering how I can check the devices LTE frequencies? Is there any engineering code and/or menu that would assist with this? This device apparently supports LTE 800 / 1800 / 2600 or LTE 700 / 800 / 1700 / 1800 / 2600 according to GSM Arena. I am wanting to use the LTE 1800MHz frequency in Australia, though cannot get it to connect.
I have tried the following:
Searching for networks manually / letting the device select them automatically
Toggling between 3G only and Automatic (4G/3G/2G)
I definitely have the correct APN settings configured (for Telstra in Australia)
Data is enabled, the SIM card connects to 4G in another mobile
Any assistance would be appreciated, in finding out which LTE network frequencies this device supports.
Click to expand...
Click to collapse
Do not rely on GSM Arena those guys are rookies.
The Rogers RAZR HD has LTE 700/1700/2100 via the rogers website.

MarrkDaviid said:
Hey Guys,
I have a Motorola RAZR HD XT925 which was sourced from Rogers Canada. I was wondering how I can check the devices LTE frequencies? Is there any engineering code and/or menu that would assist with this? This device apparently supports LTE 800 / 1800 / 2600 or LTE 700 / 800 / 1700 / 1800 / 2600 according to GSM Arena. I am wanting to use the LTE 1800MHz frequency in Australia, though cannot get it to connect.
I have tried the following:
Searching for networks manually / letting the device select them automatically
Toggling between 3G only and Automatic (4G/3G/2G)
I definitely have the correct APN settings configured (for Telstra in Australia)
Data is enabled, the SIM card connects to 4G in another mobile
Any assistance would be appreciated, in finding out which LTE network frequencies this device supports.
Click to expand...
Click to collapse
XT925: (international)
Secondary Cellular Networks: LTE700 (B17), LTE1700/2100 (B4), LTE1800 (B3), LTE2600 (B7), LTE800 (B20)
From what I've read, B3 is Australia's LTE band, so it is supported, but it might be turned off in roger's radio.
Have you tried installing the firmware for Telstra? It's available here: http://sbf.droid-developers.org/van...25_A045_WIG149790_Service1FF_fastboot.xml.zip from this thread: http://forum.xda-developers.com/showthread.php?t=1943879 Maybe switching to your provider's firmware will fix the LTE issue.

Hi
Can you please provide an update. Did you manage to flash the Testra fw and latch in to the LTE 1800 band?
Coz i would like to buy a phone and do the same thing as you. I would not buy if you did not suceed.

MarrkDaviid said:
Hey Guys,
I have a Motorola RAZR HD XT925 which was sourced from Rogers Canada. I was wondering how I can check the devices LTE frequencies? Is there any engineering code and/or menu that would assist with this? This device apparently supports LTE 800 / 1800 / 2600 or LTE 700 / 800 / 1700 / 1800 / 2600 according to GSM Arena. I am wanting to use the LTE 1800MHz frequency in Australia, though cannot get it to connect.
I have tried the following:
Searching for networks manually / letting the device select them automatically
Toggling between 3G only and Automatic (4G/3G/2G)
I definitely have the correct APN settings configured (for Telstra in Australia)
Data is enabled, the SIM card connects to 4G in another mobile
Any assistance would be appreciated, in finding out which LTE network frequencies this device supports.
Click to expand...
Click to collapse
Hi. This is a good source here in Australia. Hopefully is updated and current. http://whirlpool.net.au/wiki/mobile_phone_frequencies
Note, however, that LTE is really new here and not yet well implemented. I live in Sydney, but I'm outside of the LTE network at home. I'd have to travel closer to the business district to get it. I think its implemented around the airport as well. LTE is still a work in progress and Telstra is ahead of the game with the other telcos, but you're going to want to be able to connect to their "Next G" or 3.5 G to fallback on otherwise youre going to get 2G.
In any case, you want to make sure your APN settings are correct as well. There is loads of misinformation about that. You can have Telstra set them for you (or at least it worked on my Galaxy S2, haven't tried with this phone since I got it from their store). Try this link and see if it the correct one: http://www.configure.telstra.com.au/telstra/index.jsp
On my Galaxy S2, I had read lots of documentation and had things working but found that after going through a Telstra automated thing (I think the above link), that it set my APNs for me and I ended up with better speed and signal.
Just found this from their site as well concerning their 4G and 3G frequencies: http://www.telstra.com.au/mobile-phones/coverage-networks/networks/
The 2100 frequency on their 3G or NextG (3.5G) may have been turned off at this point; I don't remember. They may still be using it for legacy phones and people on bring your own phone plans but I beleive they had wanted to either shut it down or sell it to another carrier. I don't recall that my SGS2 got 850 ... I just noticed there's tabs on the Telstra page that explains their coverage. Click on them and that's more accurate than what I just typed
I suspect your problem is that you may not be in an LTE covered area. Either that or its your APN settings. Let us know how it goes.
EDIT: Sorry, I didn't read your post properly that the SIM works in another device. If it isn't your APN settings, you can take it to a Telstra store and ask them if they know what the problem is. On occasion they do know what their talking about. You can point them at this web page if need be and it might encourage them to look a little deeper:
http://www.morecellphone.com/compar...d-xt925-vs-motorola-droid-razr-hd-xt926/39060
[

pandabear said:
Can you please provide an update. Did you manage to flash the Testra fw and latch in to the LTE 1800 band?
Click to expand...
Click to collapse
I no longer have this device, and unfortunately never tried flashing the Telstra firmware on the device.
PantsDownJedi said:
you can take it to a Telstra store and ask them if they know what the problem is. On occasion they do know what their talking about.
Click to expand...
Click to collapse
The device that I had was sourced from Rogers Canada, and didn't support LTE 1800MHz out of the box. They wouldn't have been able to help.
PantsDownJedi said:
The 2100 frequency on their 3G or NextG (3.5G) may have been turned off at this point; I don't remember. They may still be using it for legacy phones and people on bring your own phone plans but I beleive they had wanted to either shut it down or sell it to another carrier.
Click to expand...
Click to collapse
Telstra's 3G 2100MHz network was part of 3GIS, an agreement between Telstra and VHA, which ended on August 31st. Telstra still uses the 3G 2100MHz network frequency, it is actually part of their Next G network now, they however do not advertise this, as very few sites are still using this network frequency, and it is far more important to have a device that supports 3G 850MHz. Telstra lost quite a few 3G 2100MHz sites when 3GIS closed, although all of the areas would have had 3G 850MHz anyhow, so it was not really a big deal.

[Q] 1800MHz LTE Band

This phone is the first phone Verizon is selling (except the iPhones) that has the 1800MHz LTE Band (band 3).
When I saw this I was particularly excited as I visit Australia often and that's the band Telstra uses. I am currently in Australia now, and I am unable to pick up any LTE on this phone. I have gone through every possible mode in the phoneinfo app, but none will get any LTE signal.
I am using a Telstra SIM that has LTE service and I put in the correct APN settings.
The only possible explanation that comes to mind is that Verizon is blocking the 1800MHz LTE band from being used, just like the S4 came with AWS but only a software update pushed later on was able to unlock that band. If that were the case, is there any way around it?
Any other ideas why it's not working?

I tested my SIM in the same location in a iPhone and it got lte
Sent from my HTC One M8 using Tapatalk

levilib said:
This phone is the first phone Verizon is selling (except the iPhones) that has the 1800MHz LTE Band (band 3).
When I saw this I was particularly excited as I visit Australia often and that's the band Telstra uses. I am currently in Australia now, and I am unable to pick up any LTE on this phone. I have gone through every possible mode in the phoneinfo app, but none will get any LTE signal.
I am using a Telstra SIM that has LTE service and I put in the correct APN settings.
The only possible explanation that comes to mind is that Verizon is blocking the 1800MHz LTE band from being used, just like the S4 came with AWS but only a software update pushed later on was able to unlock that band. If that were the case, is there any way around it?
Any other ideas why it's not working?
Click to expand...
Click to collapse
Bit of a necro-post, but I asked both HTC and Verizon associates and they said that it should work...so don't know if some bad information has been passed my way or GSM/LTE is just being funky (I do remember reading that has been, or was, a problem)

Unlocking LTE Bands

Hey guys,
I'm really interested in picking up a 4c, and would be even more inclined to do so if LTE bands can be unlocked (Ideally bands 2, 4 and 12).
This has been done successfully in the past on Xiaomi devices (specifically the Mi Note Pro with the Snapdragon 810). Since the 808 shares a very similar architecture to the 810, I'm hoping it can be done on the 4c successfully.
Here are some resources and guides to start with:
http://forum.xda-developers.com/redmi-note/general/unlock-lte-bands-step-step-xiaomi-mi-t3084774
http://en.miui.com/thread-154862-1-1.html
http://forum.xda-developers.com/mi-...how-to-unlock-lte-frequency-bands-mi-t3215880
http://forum.xda-developers.com/oneplus-one/general/guide-unlock-aditional-bands-qualcomm-t2877031
http://www.xda-developers.com/remove-band-restrictions-qualcomm/
Hopefully someone with a Mi 4c is able to try and confirm their success!

That's very interesting! I wish also band 20 (800 MHz) could be unlocked since it's largely used in Europe.

Mee too interested to unlock (if possibile) 800 mhz

One more interested in the 800. :good:

B4 (AWS)
Im up for B4 (AWS) :good:

doesn't have it unlocked but it seems it makes really no difference. Don't trust the few articles from people who did not even test...
I have LTE bands everywhere (work, home, way between) and I live in a zone where it is kinda hard to get...

exploreresp said:
doesn't have it unlocked but it seems it makes really no difference. Don't trust the few articles from people who did not even test...
I have LTE bands everywhere (work, home, way between) and I live in a zone where it is kinda hard to get...
Click to expand...
Click to collapse
It depends a lot on what network you're on. The LTE bands that come enabled by default on the 4C don't support any US networks.

800 mhz (band 20) would be great

What LTE bands does mi4c support?
Does anyone know what LTE Bands the Xiaomi mi4c supports out of the box?
Been struggling to find a reliable source/list

boonkoh said:
Does anyone know what LTE Bands the Xiaomi mi4c supports out of the box?
Been struggling to find a reliable source/list
Click to expand...
Click to collapse
2G GSM 850/900/1800/1900MHz; CDMA BC0/BC1
3G WCDMA 850/900/1900/2100MHz; CDMA BC0/BC1
4G FDD-LTE: 1800/2100/2600MHz; TDD-LTE: Bands 38(TD 2600) / 39(TD 1900) / 40(TD 2300) / 41(TD 2500)

800MHz?
Hi,
Bought mi4c to find out that I can't get LTE working in my village
I live 12kilometers from a bigger city. There is LTE available in my village but I think they operate on 800MHz and in city at 1,6GHz.
I dreamed about using my new 4g connection here after 3years with Galaxy S3
I have to try these guides. Thank you for providing them.
Regards,

Noboby tried to unluck bands?

Wouldn't advise in case it bricks the phone. If there is a way to unbrick, then go for it it

ermacwins said:
Wouldn't advise in case it bricks the phone. If there is a way to unbrick, then go for it it
Click to expand...
Click to collapse
In Snapdragon phones there is always a way to unbrick but it could be very frustrating and time intense

I have tested it on many of my snapdragon phones.
On some phones, it works flawlessly. On other, the signal strength is weaken but works nevertheless. However, some phones especially carrier ones have anti tampering mechanism which reverts the value back to original after restart. However, usually this is solved by a custom kernel and custom rom but then again, it gets really tough to get into diag mode in custom modes.
Never had any problems.
But you MUST backup your EFS partition via recovery or using QPST / QXDM else you would have a lot of problems if you messed up the values like no signals or broken wifi or sensors etc. and SAVE them on your phone as well as on your PC. (at least two backups)
As long as you take the above two precautions, you will never mess up your phone!

Its supports LTE band 3 and 7 which is mostly used in europe, middle east and asia. However even after you select "Prefer LTE" from the setting it might not connect.
You can try this (this will change on reboot so will try to see if i can change within the code):
1. Enter *#*#4636#*#* in the diapad.
2. Select phone information 1 (there are two sims so select the first one)
3. Change to LTE/WCDMA (if it doesn't connect to LTE then try "LTE only" and then change it to LTE/WCMDA)
If the above doesn't connect to LTE then your carrier is offering LTE at a different frequency.
For me atleast the default APN were wrong, so i had to manually change the APN restart and then do the dialer thing.

regspy said:
3. Change to LTE/WCDMA (if it doesn't connect to LTE then try "LTE only" and then change it to LTE/WCMDA)
Click to expand...
Click to collapse
There is NO LTE/WCDMA option only. Please see screenshot and point out what option I'm supposed to pick
screen shot of "phone information 1" --> http://imgur.com/BELHKaO
Which one of those am I supposed to tap on?
I picked "TD-SCDMA, WCDMA and LTE" but that broke network connectivity.
EDIT: Please also take a look at this: http://imgur.com/gallery/yzIHD49
I am currently connected to "3 ITA 3G" and would like to connect to "3 ITA 4G" but tapping on that makes a pop up appear "Registered on network". However no 4G appears in the bar on top. It remains stuck in 3G or H+.
3 ITA doesn't have LTE on band 20 [8oo Mhz LTE].
So why aren't I picking up 4G?

@AndrewIT im not in italy, however from Wiki it seems your carrier supports 4G on band 3 (1800).
select the "3 ITA 4G", then follow my steps. You have to scroll up that list in screenshot http://imgur.com/BELHKaO and you'll see "LTE only" and "LTE/WCDMA" option.

regspy said:
@AndrewIT im not in italy, however from Wiki it seems your carrier supports 4G on band 3 (1800).
select the "3 ITA 4G", then follow my steps. You have to scroll up that list in screenshot http://imgur.com/BELHKaO and you'll see "LTE only" and "LTE/WCDMA" option.
Click to expand...
Click to collapse
Thank you! I was finally able to see the 4G icon on my Mi4c.
Entered *#*#4636#*#* in the diapad.
Selected phone information 1 (there are two sims so select the first one)
I scrolled up [see screenshot] and set WCDMA and LTE from the list.
Screenshot: http://imgur.com/OJ98uQi
You can see that I successfully picked up 4G signal, but it was extremely poor, only one bar standing close to a window.
As I move inside the house it loses 4G and gets back to 3G or H+.
It seems that I'm way too far from the LTE antenna to get a good 4G signal.

Guys I am kinda lost here, so is there a good chance that it supports especially 800Mhz band or not ? And when I am here, is there hardware difference between TDD-LTE and FDD-LTE version? How do I find out which one I have ?

PLEASE HELP! Network no longer connecting on new Moto G3 TE (merlin)

Please help! Network issues - will *not* connect at all anymore!
I just bought this phone (XT1557) just over a week ago. I unlocked it and installed TWRP then made a backup. Then I installed AOSP Extended and was enjoying learning about it and using the phone. I'm using H20 Wireless (they use AT&T network). Everything seemed to be great for about a week and I was very happy with my new phone. However, just yesterday, while traveling in the US and using the phone (for maps/navigation, gasbuddy, facebook, etc. - it was also charging from a car charger at the same time) we hit a patchy spot in the signal and I couldn't get the network to reconnect. After a few minutes (still traveling) for a split second the network icon flashed as having a decent signal, but then it went off again and *NEVER CAME BACK*! Nothing I've done since then has been able to get the network to come back on my phone.
Here's what I've tried:
* toggling airplane mode, toggling preferred 4G/LTE, or 3G, or 2G
* Reboot;
* safe mode;
* tried sim in the other sim card slot
* tried another sim in my phone that was currently working at the time in Moto G 2nd gen, in both sim slots - still not working in my phone; tried my sim in that phone and it's working in that phone (so not a sim card problem)
* tried *#*#4636#*#* - still shows "emergency calls only" and the signal strength does fluctuate depending on where I move around (see screenshots), tried bunch of different radio bands, tried turning off and on radio power, tried changing preffered network type (to lots of different ones)
* tried dirty flashing AEX again and newest GApps
* tried clean flashing AEX and newest GApps
* tried clean flashing Lineage OS 14.1 and newest GApps.
* flashed only the original modem firmware from MM stock rom (provided here at xda)
* restored my nandroid backup to stock rom (6.0.1)
NONE of these things have worked! PLEASE help! Is there any way I can test this to see if it's a hardware issue? (Though it seems strange for hardware to fail after just 1 week... and there's no warranty since I unlocked it, but I bought it new on ebay anyway, so no warranty.)
Any help you can give will be so appreciated. Nothing else on the phone seems to have a problem (wifi, etc., all seem to be working). The phone didn't even act weird when the network stopped working -that was the only thing. Everything else on the phone still acted like normal without even a reboot. If you've ever even heard of this happening, please let me know. I can't find any other info on what to do on the internet and I've searched all over. If you can help me (or even try), I'll give you so many thanks, as many as it lets me give on here! Thank you for even considering helping me - I really want this to work!

I don't know for sure if this is the case, but here is a possibility...
There is no 2G (GSM) service on H2O/AT&T, period, it was shutdown in December 2016.
For 3G AT&T uses 850Mhz & 1900Mhz HSPA(+), but it varies which one based on licensing and network saturation, among other things... Not everywhere has both (in fact, both only appear in select high-penetration markets)... the XT1557 supports HSDPA 850/900/2100, note that 1900Mhz is NOT a supported frequency, yet it is quite common in AT&T's network... It is a possibility that you left an area with 850Mhz service, and entered an area with 1900Mhz service and now have no service, literally. The service is there for AT&T/H2O, but your phone doesn't support the frequency in that area.
LTE bands support by the XT1557 are LTE band 1(2100), 3(1800), 7(2600), 8(900), 28(700), 40(2300), but none of those are compatible with AT&T.
It is entirely possible that you just don't have service, because there is NO service your phone is capable of getting because either that frequency isn't available or it's used by another carrier in that area (and H2O has no roaming from AT&T's core network to partner networks like AT&T post-paid service).
Just a possibility... but basically you have a device that only supports a portion of the network you are trying to use.

acejavelin said:
I don't know for sure if this is the case, but here is a possibility...
There is no 2G (GSM) service on H2O/AT&T, period, it was shutdown in December 2016.
For 3G AT&T uses 850Mhz & 1900Mhz HSPA(+), but it varies which one based on licensing and network saturation, among other things... Not everywhere has both (in fact, both only appear in select high-penetration markets)... the XT1557 supports HSDPA 850/900/2100, note that 1900Mhz is NOT a supported frequency, yet it is quite common in AT&T's network... It is a possibility that you left an area with 850Mhz service, and entered an area with 1900Mhz service and now have no service, literally. The service is there for AT&T/H2O, but your phone doesn't support the frequency in that area.
LTE bands support by the XT1557 are LTE band 1(2100), 3(1800), 7(2600), 8(900), 28(700), 40(2300), but none of those are compatible with AT&T.
It is entirely possible that you just don't have service, because there is NO service your phone is capable of getting because either that frequency isn't available or it's used by another carrier in that area (and H2O has no roaming from AT&T's core network to partner networks like AT&T post-paid service).
Just a possibility... but basically you have a device that only supports a portion of the network you are trying to use.
Click to expand...
Click to collapse
Wow, this info could be SOOO helpful! I know this is only a possibility, but it gives me a glimmer of hope when I thought the phone was doomed/broken somehow. I did know my phone was only partially supported (like I knew I probably couldn't get LTE in the US), but I didn't know what all that meant in terms of the other bands. I bought the phone for primary use in Madagascar (which my phone appears to cover all the bands used in Madagascar) but I won't be back there until September, so I'm using the phone in the US in the meantime.
Even though I considered my phone/SIM might not be compatible with the local network, I figured that couldn't be the case since there was clearly a signal in the Moto G2 XT1068 (Titan). However, with what you explained, that might explain some other anomalies. My Titan is also a phone made for international use (where I've used it for years in Madagascar and South Africa and it works great), but when traveling here in the US, I've noticed some anomalies that your explanation might explain (assuming the Titan might also have limited frequencies in use by AT&T/H2O in various parts of the US). For example, in Alaska,there was a time when in southern Alaska (inside passage) my Titan worked great, voice/data, everything (even in some way out of the way places)... then later in central Alaska my wife's phone (an old AT&T phone with a post-paid AT&T sim) got a data signal, and my Titan got a voice signal but no data. It was strange. Didn't work in some airports along the way either (I don't remember which ones, maybe Chicago). It wasn't until we were back in St Louis that the data started working on my Titan right away again, no problem. I figured it was some strange glitch of the OS (CM 13.1) in how it searched/recognized the local network. But maybe it was a limit in the phone's available bands in those regions of the US?
Then again, after I got the new XT1557 (just over a week ago), I transferred my wife's AT&T postpaid SIM to my old titan (XT1068). It was working great, but I never thought to check her mobile data away from wifi (just got busy and never thought to check). At the same time we hit the spotty network connection while travelling 2 days ago (northeastern Missouri, the network was spotty and cutting out on both our phones), that was when my signal went out for good and I saw that hers (AT&T postpaid but now in a Titan XT1068) didn't have a data signal when her network/voice signal came back. That made it very difficult to navigate, so we stopped and refreshed our maps at public wifi. I thought maybe I just needed to update the APN with AT&T, but when I manually input the info they gave me, it still didn't give me a data signal (on the Titan). Now we're in the Des Moines, Iowa area and I'm experiencing everything I've written about with my phone having never recovered a network signal. However, the one anomaly is that, even when I put my H20 sim back in my Titan XT1068 (which I thought was always working in the past, minus that anomaly from the Alaska trip) it gets a good voice signal but still no data signal, just like my wife's prepaid AT&T never got a data signal (that I could see), and even though I know which APN settings to use for H20. I've similarly been beating my head in over the titan's lack of data signal since I refreshed the OS (now on Lineage OS 13.1) since it means we have 2 phones with us on this trip, neither able to get data since leaving northeastern Missouri and mine even worse getting no voice signal at all.
But maybe it means my Titan XT1068 also has limited bands that aren't covered by AT&T/H20's data here even though it's covered by their voice?
The info you've provided so far is excellent. Can you provide similar info about the XT1068's available bands? (I'm not sure where to find all that - I found the original info about XT1557 in the wikipedia page, but Moto G 2nd gen doesn't seem to list the bands specifically. I also don't know where to look for AT&T's specific bands and/or coverage map that might indicate where they have coverage with each band.) If you can provide any of that info it would be so great! But for now, you've extended my hope for my phone. We'll be in Minneapolis area in a few days, so maybe I can try again there. Then we'll be back in St Louis area (where it was working great previously) in just over a week. So at least I'll hold out my hope until then and maybe I'll discover this just isn't the best travel phone for northern US (or other parts of the US). Still, I can't thank you enough for the hope you've given me, even if it is *just* a possibility. It does seem to explain the circumstances.
Sorry for the long story! I just wrote to show that your explanation might really fit well! Your info was so helpful! Please follow-up to tell me if you think the extra info I gave confirms what you wrote. Please also help me find a coverage map for AT&T where I can see where in the US they use specific frequencies. If you can do that for me. Thanks again for being so helpful and explanatory!

@madagascaradam Search by model and then and find the GSMArena page for the device, under the Network section click Expand...
2G bands GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2
3G bands HSDPA 850 / 900 / 1700 / 1900 / 2100
Speed HSPA 21.1/5.76 Mbps
GPRS Yes
EDGE Yes
Click to expand...
Click to collapse
So the Moto G2 you have supports the proper HSPA (but hot HSPA+) bands for all AT&T's 3G frequencies.
Remember that prior to December of last year, likely when you were referencing your Alaska trip, there was AT&T 2G/Edge service nationwide but that has since been shutdown and within the next 2-3 years all 2G GSM and CDMA service in the US will be shutdown from all carriers.
And I used H2O for quite a while, use this APN (there are lots of older settings out there, they don't work quite right, but this is current as of a month or so ago at least):
Name: H2O Wireless
APN: prodata
MMSC: http://mmsc.mobile.att.net
MMS Proxy: proxy.mobile.att.net
MMS Port: 80
MCC: 310
MCN: 410
Authentication Type: Not set
APN type: default,mms,supl,hipri,fota
APN Protocol: IPv4
APN roaming protocol: IPv4
everything else blank, not set or none.

@acejavelin You were totally right! In Minneapolis area I usually had a signal, but not much outside the area. In Iowa no signal at all. But once I got back towards central Missouri the signal has been working great again. So obviously ATT has some regions that use 850 (like in the south) and others further up north that seem to only use 1900 which isn't supported by my phone (XT1557). So, that's not super great for using my phone in the US, but at least I know it's not a problem with my phone.
I also found this map (older, from 2008) which shows where AT&T had 850 MHz frequency and where it had 1900 MHz frequency. It roughly corresponds to my experiences so I definitely think it all adds up. http://www.cellularmaps.com/att_850_1900.shtml
Again, thanks so much for your help!