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LTE connection failure

Problem: The gateway cannot establish an LTE connection despite a correctly installed SIM and APN. Cause: The modem needs to be recovered, or its automatic operator selection failed to connect to your carrier. Solution: Use the modem-tools helper to check the modem, retry the connection, and — if needed — select your operator manually. This is a command-line procedure.

Recover the modem with modem-tools over SSH

Open an SSH session to the gateway. Run senarch-help to list the available helper commands, including modem-tools. modem-tools talks to the modem for you, so there is no need to toggle GPIO power lines or open a serial terminal by hand.

Start by checking the modem and retrying the normal connection.

Check the modem state:

modem-tools status

Retry the normal connection path:

modem-tools connect

If it still fails, power-cycle the modem and rebuild the data path:

modem-tools cold

Run a bounded AT diagnostic sequence:

modem-tools diag

Force the operator manually

If your carrier is still not selected automatically, force the operator with the at passthrough.

Check the current operator:

modem-tools at "AT+COPS?"

Scan for operators:

modem-tools at "AT+COPS=?"

Select your operator (replace 23801 with your operator's code from the scan results):

modem-tools at "AT+COPS=1,2,\"23801\""

Verify:

modem-tools at "AT+COPS?"

Return to automatic selection:

modem-tools at "AT+COPS=0"

Reboot the gateway and confirm LTE connectivity. The modem should connect automatically on future restarts.