A reader, Joseph, asks,
Can I use my US Cellular Samsung Galaxy S5 with Straight Talk Wireless> Its a CDMA phone and the model number is SM-G900RZKAUSC. What do I need to do?

I don’t know. You can check if this phone is eligible yourself online at straighttalk.com. To learn how to check this see Checking If You Can Use Your Verizon Smartphone with Straight Talk Wireless. Check out the video and see if you phone is compatible with Straight Talk’s Verizon network. If not repeat the process and see if your phone is compatible with the Straight Talk Sprint network.

When you sign up for Straight Talk, your phone is placed on either Straight Talk’s ATT, Verizon, Sprint, or TMobile network. You want to pick the network that works well where you plan to use your phone and the network that is compatible with your phone.

Your Galaxy S5 (SM-G900RZKAUSC) might also compatible with the Straight Talk’s AT&T and Straight Talk’s T-Mobile network. You’ll need the Straight Talk micro SIM for the network you want to use. Your phone will need to be SIM unlocked. Your S5 may already be SIM unlocked. The easiest way to check this is borrow a AT&T or T-Mobile micro SIM from a friend and put it in your phone. If it works, your phone is unlocked. If your phone is not unlocked, check to see if you qualify for US Cellular to unlock it. See http://www.uscellular.com/site/legal/mobile-wireless-device-unlocking.html

I looked at the specification for the US Cellular Samsung Galaxy S5(SM-G900RZKAUSC) but I can’t tell if the phone if or how well this phone will work on Straight Talk’s AT&T, Straight Talk’s Verizon, Straight Talk’s Sprint, or Straight Talk’s T-Mobile network. For your phone to work, first those networks need to have network coverage where you use your phone. Second your phone needs to support the same cellular radio signals that those networks do. As far as I can tell this verison of the Galaxy S5 is partially compatible.
You can see the network specs for your phone here. http://www.gsmarena.com/samsung_galaxy_s5_cdma-6338.php
http://www.samsung.com/us/support/owners/product/SM-G900RZKAUSC

The specifications for the AT&T and T-Mobile variants here http://www.gsmarena.com/samsung_galaxy_s5-6033.php

If you are trying to figure this out, leave a reply below and I’ll try and help you out.