Hello,
Product code RUT2400D**** means that this device has a MeiG mobile module. It is intended for the Europe, the Middle East, Africa region.
Other RUT240 models are approved for the US market. These are RUT240 *1**** and RUT240 *2****:
https://wiki.teltonika-networks.com/view/Frequency_Bands#RUT240
Only they have the necessary approvals from AT&T or Verizon operators.
A different product code means hardware changes, the device has a different mobile module and supports different frequencies. You must order another device according to your region and operator.
Best regards.