Question Differences with 2 SIM cards in the "Preferred networks" tab

[aarone]

Hello all. Thank you in advance for taking the time to read this mystery
When I insert a Verizon [only] SIM card into my device, it allows me to select LTE/CDMA, LTE/GSM or GLOBAL in the Preferred Networks tab. However, the only setting that works is LTE/CDMA. I understand that's because Verizon is CDMA so I am good with that....
--> now for the fun...
When I insert a multi-carrier SIM card in the same device, the Preferred Networks tab changes what the available options are. They are 4G, 3G or 2G. Ofcourse I select 4G because there is no sense in selecting any other option. The device works well on AT&T and Tmobile (GSM) roaming between both operators however it will not roam onto Verizon (CDMA)
I believe it's because the device thinks it's only looking for a GSM operator.
I put that exact Multi-carrier SIM card into another device that uses a Linux operating software and allows me to select "AUTO" on the network tab. This radio works very well as it switches between all operators. All 3 carriers work fine! AT&T, T-Mobile and Verizon!

Anyone with proTIPS that can assist me? My question is, would there be an APN I could load that can steer the radio into looking for GSM or CDMA as needed?
Is there another setting or operating system software I could ask my Manufacture to load into the Android device that would allow "AUTO"?

The radio device is running V7.1.1 (although I noticed it on V10 also)

Thanks a ton!

 

[Laura Knotek]

Verizon shut down the CDMA network. There aren't any USA carriers that still have CDMA. https://www.phonearena.com/news/ver...31st, 2022, if,messages, or use data services.

 

[aarone]

Thanks for the speedy reply! I get it.. I read that and I knew they were shutting down the CDMA network well over a year before they actually did it however, as indicated in my message, that is the only way I can get the Verizon data to work in my device (selecting LTE/CDMA versus any other option.
In my multi-carrier card, for some reason, I do not get that option. I only get 4G, 3G or 2G. In my linux radio, I only get "Auto" and it simply works on all carriers. I have specifically identified a Verizon only service zone which I can consistently test.