[FYT Android Head Units] tRidiot:
So when I first got this unit (sc9853i) from Joying, I managed to get a regular Straight Talk SIM card (on AT&T network) to work and I had data access - but pretty poor. I always assumed it was just the Joying cellular radio was bad, I don't know, I would sit and circle, circle, circle looking for signal even in the middle of major metropolitan areas.

Then I blew a head gasket in my truck and it was 6 months getting fixed, so I didn't keep paying for the service. Later I couldn't get it to hook up again, so I went and bought a new SIM packet for Straight Talk and never could get the card to work, even with Straight Talk support.

Then I went to AT&T and got a card from them to put on my plan, but it wouldn't work, either - never connected, eventually they told me my device was an old 3G unit and was no longer supported by the AT&T network.

So I tossed all the cards and just used my WiFi hotspot off my phone. However, recently I got stuck in McKinney, TX trying to use my GPS and my phone and Google maps weren't playing well together for some reason. So I decided to maybe try again.

I got an email back from Joying support when all this was going on and this is what they told me:

"Please check the following information:

Support types

GSM: GSM850 EGSM 900 DCS1800 PCS1900

WCDMA: BAND1 BAND2 BAND5 BAND8

TD-SCDMA: BAND34 BAND39

TDD-LTE: BAND34 BAND38 BAND39 BAND40 BAND41

FDD-LTE: BAND1 BAND2 BAND3 BAND5 BAND7 BAND8 BAND20 BAND29A

Not supported types

AT&T: BAND12 BAND14 BAND17 BAND29 BAND30 BAND66

Verizon Wireless: BAND13 BAND66

T-Mobile: BAND12 BAND66 BAND71

Sprint: BAND25 BAND26 BAND41"

Can anyone tell me how in the world I can guarantee a prepaid service or card I get from somewhere will fit these criteria? Are there ANY US carriers that will work with this unit anymore? I mean, it says no to AT&T and Verizon, and I believe Verizon bought Straight Talk... am I SOL on having SIM-based network access on this unit now?

I also just ordered one of the newest 8" Qualcomm-based units from Joying to put in my wife's new (to us) 2018 Toyota RAV4 - I really want her to also have SIM-based network data that doesn't have to rely on her phone's hotspot. That unit shows THIS compatibility chart:

Supported Micro SIM cards type:

�

GSM​

GSM850 EGSM900 PCS1900

WCDMA​

BAND2 BAND4 BAND5 BAND8
SIM Cards Type

TDD-LTE​

BAND38 BAND41

FDD-LTE​

BAND2 BAND4 BAND5 BAND7 BAND8 BAND12 BAND17

So my question is, with these two units (and a likely 3rd I would like to buy for my 370Z), can you explain to me how I know when I'm buying a SIM card prepaid setup if it will work with these? And not get shafted on a packet like last time, where I had to pay the $50 or $60 to activate the plan and then find out the card won't work in my unit? AT&T told me my problem was an old 3G unit - but this is obviously untrue, previously I was connecting with a 4G signal.

I just would like to be able to get SIM-based network access, so I don't have to rely on my phone's hotspot, turning it on and off, etc.

<edit> I highlighted the overlapping bands between the two units that should work - I just need to find a carrier that uses these and has decent 4g LTE prepaid service, if anyone can point me in the right direction.