GPy LTE module questions

  • I am trying to gain a deeper understanding of the LTE modem and the Pycom LTE module that interfaces with it. I have had good luck getting my GPy connected with the vanilla LTE module and a sim card here in North America (Phoenix). However, it is exclusively connecting to AT&T. As I start to branch out and set the carrier in the pycom module, or even try to scan towers or force Verizon via AT commands I'm having very limited success. Here are some of my questions I'm left with after my experimentation:

    1. lte.send_at_cmd is documented as having a delay parameter, but trying to set that gives me: TypeError: extra keyword arguments given. I'm trying to set this since a number of my AT commands appear to be timing out. Is the documentation incorrect?
    2. I was trying to review source here: to get an idea of what the LTE module is doing but I can't seem to recreate behaviors by running the AT commands its using, or vice versa. For example in the C code it looks like lte.init(carrier='verizon') calls AT+SQNCTM="verizon" but if I check AT+SQNCTM? after calling init it's still set to standard. Does this code not reflect what's in the GPy firmware?
    3. AT+COPS=? seems to be timing out and giving me errors regularly, is this normal?
    4. I can set lte.init(carrier='verizon') and still end up attaching to AT&T. Is this expected behavior?

    In short I want to know if there's something different I can be doing to get the device to attach to other providers to improve my coverage. Or even if there's a way to get reliable tower scan data from the device to know if there are other providers available.

    This is my output from

    >>> import sqnsupgrade
    <<< Welcome to the SQN3330 firmware updater [1.2.6] >>>
    >>> GPy with firmware version 1.20.2.r1
    Your modem is in application mode. Here is the current version:

    1. the at cmd time delay has gone the way of the dodo
    2. almost certainly
    3. cops cmds return errors if the modem is not attached
    4. if your hologram sim is a multi-carrier sim it should connect to the strongest carrier, if it's a single carrier sim it it will only ever use that carrier

Log in to reply

Pycom on Twitter