Connecting to the LTE network

I have a XBee TH Development board with an LTE modem card.
When powered up, I can read the SW version, the IMEI and the IP address.
When I take that same modem card and place it on our custom HW,
I can read the SW version and the IMEI, but my IP address is
The modem is not connecting to the network in our custom HW setting.
Is there a document that would describe the AT commands required to
get the modem card to initiate connection to the LTE network?

Thanks in advance!

As far as the XBee Cellular modules are concerned, the same commands are used to both function on a Digi interface board as it would on your board. That is to say, there are no special commands you need to use that tells the radio to obtain an IP address that are different than what you would use on the interface board. To be more specific, as long as you have a valid SIM card entered, the correct APN, the antennas connected and the proper power, it will provide an IP address once connected to the tower.

If I had to guess your board can’t supply enough power.