Digi XBee 3 Global LTE-M/NB-IoT not connecting to mobile network

XBee & XBee Gateway XBee - Cellular
1

I am having some dramas with a few of the units I have here.

When they are set up, they don’t connect to the Cellular network. I have set up about 60 of these units, all identically and under the same conditions, and I have a handful of them that I have collected that just refuse to connect after setup.

  • The antenna is fine, as it works with other units. Signal strength is great.
  • SIM card is fine. It works fine in other units and the problem units can read the ICCID of the installed SIM.
  • APN and band config settings are identical to working units.
  • I have sent AT commands in bypass mode, still no connection.

I’m out of ideas. It would be great to get these units working.

2

I would suggest the following commands via the XBee interface.

ATRE, ARAN (enter the APN), ATWR, ATNR

This will restore the module to defaults, set the APN and write to defaults. Then preform a network reset.

3

No luck. ATAI still returns FF. Is it possible the modem has failed? Are there other things to check that will determine if it has failed?

4

Yes, Check to see if the MV, MU, IM commands report any values.

5

The commands just return ‘OK’. This means it has failed?

6

That would generally mean that either the modem has failed or has been reconfigured for USB direct. try restoring the radio to defaults using the ATRE, WR command and then try reading the values again after a min or so.