Carrier My T-Mobile Iphone Works with Verizon

[chrisdaidai]

Here's what happened: I bought my 6s Plus in 2016 at a T-mobile retail store and after 6 month or so I decided to switch to Verizon for wider coverage and better signal.

At that time I was completely unaware of the GSM/CDMA things, so I just paid off my bill and unlocked my phone on T-Mobile's website. Then on the same day I went in a Verizon store and switched to their service without any issue.

Now that I realized that a T-Mobile/ATT iphone should not be able to work with Verizon/Sprint, I'm very curious why this happened? Or did I misunderstand anything?

Yes I've been with Verizon ever since, and I'm using 4G LTE.

 

[eneisch]

It will work on 4G LTE using voice over LTE, but if there is no 4G LTE available you will have no service instead of switching over to the CDMA network for 3G data and voice.

 

[brianric]

It will work on 4G LTE using voice over LTE, but if there is no 4G LTE available you will have no service instead of switching over to the CDMA network for 3G data and voice.

I don't think that's true on the 6S Plus, as I believe that all models supported CDMA.

https://www.apple.com/iphone-6s/specs/

 

[fr4c]

6S/6S+ was the last phone to use Qualcomm modem for all carrier models. So as long as it’s unlocked it will work on all US carriers.

Apple started using QC and Intel modem starting with the 7/7+.

 

[chrisdaidai]

It will work on 4G LTE using voice over LTE, but if there is no 4G LTE available you will have no service instead of switching over to the CDMA network for 3G data and voice.

Thanks for the reply.

I don't remember if I have been able to use 3G network because most of the time it's on 4G LTE service. I do remember though that I was able to make phone calls when there's no Internet service available when I was fishing in the mountains. At that time it showed one dot of signal while nothing on the internet section.
[doublepost=1510478825][/doublepost]

6S/6S+ was the last phone to use Qualcomm modem for all carrier models. So as long as it’s unlocked it will work on all US carriers.

Apple started using QC and Intel modem starting with the 7/7+.

Thanks for the answer.

So that means starting from Iphone 7/7+, Tmobile/ATT Iphones will not work with Verizon network even if unlocked?