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Cellular Connection Process

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I'm going through the XBee Cat-M connection status example on github (https://github.com/digidotcom/xbee-micropython/tree/master/samples/cellular/connection_status) and noticed the modem will initialize and register to the network twice.

Is this a race condition, a timeout, or can someone explain what is going on under the hood and why it goes through this process twice?

- AI Changed!
* New AI: 0xFF (MODEM_INITIALIZING)
- AI Changed!
* New AI: 0x22 (REGISTERING_TO_NETWORK)
- AI Changed!
* New AI: 0xFF (MODEM_INITIALIZING)
- AI Changed!
* New AI: 0x22 (REGISTERING_TO_NETWORK)
- AI Changed!
* New AI: 0x23 (CONNECTING_TO_INTERNET)
- AI Changed!
* New AI: 0x00 (CONNECTED)

Much Appreciated.
asked Jun 29, 2020 in Python by soterboat New to the Community (15 points)

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1 Answer

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Best answer
Soter,

Yes, it is simply that the first channel you selected that there was a tower on, did not allow the connection to occur. It could simply be that it was not a CAT M/NBiOT tower or that it did not support your carrier.
answered Jun 29, 2020 by mvut Veteran of the Digi Community (15,225 points)
selected Jun 30, 2020 by soterboat
Ah that makes sense, so a follow up question. If it iterates through channels and hangs on REGISTERING_TO_NETWORK does this mean there are no supported towers in range? Thank you for your help mvut.
commented Jun 30, 2020 by soterboat New to the Community (15 points)
Yes, I would suspect that would be the case. Either that or wrong APN depending on what the last I value was before it started over.
commented Jun 30, 2020 by mvut Veteran of the Digi Community (15,225 points)
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