Select band/channel on Transport - Sierra Module

I’m using my transport WR44R with a Sierra Module
I would like to manually select the frequency for connecting to the cellular network.
The module supports selecting the frequency using AT commands, how can I send AT commands to the module?


you can send an initialisation string to the module through the

MODEMCC 0 init_str / init_str1 / init_str2

Commands the "AT " is implied