FiPy unable to connect to T-Mobile NL (LTE-M)



  • I thought I'd copy the title from an earlier post, since I have exactly the same issue, yet slightly different results. I'm using a FiPy and a GPy for my experiments, both with the modem upgraded to :
    UE5.2.0.3
    LR5.2.1.0-48829
    Both have a SIM card, which are registered and activated on the T-Moblie IoT-Creators dashboard.
    I have been running all valiations of the default test program:

    from network import LTE
    import time
    import socket
    
    def send_at_cmd_pretty(cmd, delay=1000):
        response = lte.send_at_cmd(cmd).split('\r\n')
        print('Sent to modem: \'{}\', delay {} ms'.format(cmd, delay))
        for line in response:
            if line.strip() != '':
                print(line)
    
    lte = LTE(debug=True)
    
    send_at_cmd_pretty('AT+CFUN=1') # enable modem
    
    lte.attach(band=8, apn="m2m.public.nl")
    print("attaching..",end='')
    while not lte.isattached():
        time.sleep(1)
    
        print('.',end='')
        print(lte.send_at_cmd('AT!="fsm"'))         # get the System FSM
    print("attached!")
    
    lte.connect()
    print("connecting [##",end='')
    while not lte.isconnected():
        time.sleep(0.25)
        print('#',end='')
        #print(lte.send_at_cmd('AT!="showphy"'))
        print(lte.send_at_cmd('AT!="fsm"'))
    print("] connected!")
    

    And this is what I get:

    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |CAMPED              |
        | RRC SEARCH FSM           |CAMPED_ANY          |
        | RRC ACTIVE FSM           |IDLE                |
        | PMM PLMN FSM             |ANY_CAMPED          |
        | EMM MAIN FSM             |NULL                |
        | EMM AUTH FSM             |NULL                |
        | EMM CONN FSM             |NULL                |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL         |
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | LPP FSM                  |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    

    But it never connects. It keeps giving 'SCANNING', 'CAMPING', 'CAMPED' messages but it never shows connected. Sometimes it also gives me 'SYNCING', and 'GETTING_CELL_ID', so it looks like it is actually doing something.

    The main issue though is probably that I never get something from the 'AT+COPS=?' command. So it simply seems it can never find a network. Now this happens on both boards, so i't not likely to be radio failure. (Although I do use the same antenna for this tests)
    The AT+CSQ command returns something like 10,99 or 8,99, which seem slow, but I'm not sure what it is supposed to have.

    Did anybody succeed in connecting a FiPy or GPy to T-Mobile ? And if so, how ?



  • UPDATE : IT IS SOLVED!

    Unfortunately I'm not allowed to edit my original post, so I put this here...
    It turned out the the SIM card that I used from T-Mobile had an 'old profile'. So they provided me with a new batch, and enabled the registration on their dashboard. After registering one of the new cards, the FiPy connected within 30 seconds:

    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |CONNECTED           |
        | RRC SEARCH FSM           |CAMPED              |
        | RRC ACTIVE FSM           |CONNECTED           |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |REGISTERED          |
        | EMM AUTH FSM             |KASME_DEFINED       |
        | EMM CONN FSM             |EMM_CONNECTED       |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_ACTIVE       |
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | LPP FSM                  |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    


  • @Alexander-Pilhar Thanks again. But no, doesnt help. I even went throught the upgrade routine several times, assuming the modem would be in the ultimate default state.



  • @Cees_Meijer too bad!
    I don't remember if I also tried a factory reset:
    Pycom Docs: lte.factory_reset()

    I wish I had documented every step I took to make it work...



  • @Alexander-Pilhar Tried the lte.reset() as you suggested. Does not make any difference. It is still stuck in a 'WAIT_RSSI' 'SCANNING' - 'SYNCING' loop .



  • @Cees_Meijer try to reset the modem:
    Pycom Docs: lte.reset()

    I'm just guessing here. I remember having tried a lot of different things but not sure which did the trick at the end.



  • @Alexander-Pilhar Thanks for the suggestion. But that is something I also tried, and I had it search for more than an hour, just to make sure. But nothing happened. So, still searching...



  • @Cees_Meijer did the attach process succeed?
    If not try removing the band parameter when attaching the first time and let it do it's thing for a few minutes.
    I remember having the same issue when I started working with LTE. To me it seems like the modem first needs to scan all available bands for itself.
    Once this first attach succeeds you can add the band parameter and it should work as expected.
    I hope this helps!


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