Hello,
TRB141 is an LTE Cat1 gateway, which provides a virtual network interface via micro USB. In order for this device to be able to connect to the internet, you need to insert a Mini SIM – 2FF 1.8 V/3 V SIM card.
A side note about Greengrass. Only Teltonika RUTX series devices a able to support it.
Best regards,
Žygimantas