Modem ATI response and attachment issue

[grpatt]

I have multiple GPys which are unable to attach to the network. Whenever I send ATI command to sequens modem

from network import LTE
lte=LTE()
print(lte.send_at_cmd("ATI"))

My GPys response is:

PYCOM
FiPy
UE5.2.0.3

I have seen other users with responses:

SEQUANS Communications
VZM20Q
UE6.0.0.0

The modem is unable to attach even with reflash modem firmware. Does anyone have a similar experience?

Some other people with similar unresolved issues for reference

https://forum.pycom.io/topic/5629/gpy-loss-of-attachment-ability/4

https://forum.pycom.io/topic/4915/gpy-pytrack-modem-won-t-attach-after-firmware-upgrade/9

[kjm]

@grpatt I've had several GPYs where the modem has simply died, no RF output during attachment attempts. If you've got a CRO you can wrap a few turns of wire around the lte antenna & connect to the CRO on it's mV scale. If there is no carrier the device is history, if there is very low carrier then your antenna is plugged into the wrong antenna socket.

[grpatt]

@kjm Good to know. I have been trying to get the Monarch modem to play nice for so long with only disappointment. I might end up using Ublox or simcom too.

[kjm]

Apart from all the usual stuff (sim problems, wrong telco AP, antenna issues, etc) that will prevent attachment there can also be an issue with after firmware changes see 'Problems after Firmware downgrade' in https://docs.pycom.io/tutorials/networks/lte/

When posting, its best to give the readers as much as info as possible (gpy & modem firmware versions, have you managed attachments previously, have you changed anything recently, what telco, what country, etc). I learned this the hard way.

As an aside not all modems are created equal. I'm currently tinkering with simcom 7020E, it automatically attaches from power up. Still it is nice to have a modem & microcontroller in one neat package &, on the days when the sequans is in an attaching mood, life is good.