at_cmd_mode AT+CFUN=4 problem on modem_shell firmware

[Oguzhan Turk]

On modem_shell firmware, after entering into at_cmd_mode (at at_cmd_mode start), any AT command works fine but AT+CFUN=4 (offline) command blocks the terminal and doesn't respond back with any upcoming at command anymore. Only solution is resetting modem and entering at_cmd_mode again but it's not a proper solution. Why does it stuck on offline command?

By the way, without entering at_cmd_mode, just calling offline command on mosh directly (at AT+CFUN=4) doesn't cause any problem. The problem is only on at_cmd_mode.

[Achim Kraus]

If you search this forum, you will find some tickets, which discus what happens.

The modem tries to "release the network registration", but in many cases, this ends up in a timeout, which is about 60s.

[Oguzhan Turk]

 Achim Kraus It always stuck and doesn't come back even after 60s. Are there any solution or workaround etc?

[Achim Kraus]

Uups, sorry I missed to read your ticket precisely.

I'm not common with that " at_cmd_mode", so I don't know what happens there.

[Didrik Rokhaug]

Hi Oguzhan Turk,

I am not able to reproduce this.

Could you take a modem trace, so we can see if the problem is on the modem side?

I've attached a version of the modem shell, built for the nRF9160 DK, with modem tracing enabled.

Before you send the AT+CFUN=4 command, please send AT%XMODEMTRACE=1,2 to ensure that the modem has tracing enabled.

mosh_mtrace.hex

Best regards,

Didrik

[Oguzhan Turk]

I executed AT%XMODEMTRACE=1,2 and it returned OK and then I executed AT+CFUN=4. It stucked again and didn't produce any extra output for tracing.

I also tried your mosh_mtrace.hex but it didn't work on my dev board. Instead of proper mosh outputs it put non-human readable characters to the screen like that:

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