If you are struggling with SIM compatibility with US carriers, we recommend trying to use a SIM previously activated in a mobile phone. You don’t need to switch out your SIM from your phone to your CI Pad every ride, you can get a SIM, activate it in your phone, make sure everything works and then transfer it to your CI Pad. So far, we only have evidence of this working with T-Mobile. It is possible that it could work with other carriers as well. Please send us feedback regarding this issue as it is hard for us to test since we are not based in the US.