+C5GREG? does not report any output from mmcli

Amol Lad Amol.Lad at 4rf.com
Fri Feb 3 09:49:21 UTC 2023

Thanks Aleksander,

Does "mmcli --get-cell-info" returns the cell info like tac, ci from the last URC received from the modem? Basically, if URC is not received from the modem then is it possible that --get-cell-info report stale cell information (if the device is moving)?


-----Original Message-----
From: Aleksander Morgado <aleksandermj at chromium.org> 
Sent: Friday, 3 February 2023 3:01 PM
To: Amol Lad <Amol.Lad at 4rf.com>
Cc: ModemManager (development) <modemmanager-devel at lists.freedesktop.org>
Subject: Re: +C5GREG? does not report any output from mmcli

> I'm trying on MM 1.20.4 and noticing that AT+C5GREG? (and also AT+CREG?) do not report any output when called from mmcli.
> # mmcli -m 0 --command=AT+C5GREG?
> response: ''
> # mmcli -m 0 --command=AT+CREG?
> response: ''
> # mmcli -m 0 --command=AT+C5GREG=?
> response: '+C5GREG: (0-2)'
> +C5GREG? (or +CREG?) is correctly reported using minicom so modem does responding to these commands.
> Any idea what could be going wrong? I'm trying with Telit FN990 but looks like this is a generic issue.

ModemManager has a mechanism to process URCs coming in the AT response flow. Your command response is being "eaten" by this mechanism, which ModemManager processes as a URC.
This is a known limitation of --command; at the end ModemManager cannot ensure that a real valid +C5GREG URC is interleaved between your command and your response. I guess we could try to improve that, but I'd prefer to suggest not using +C5GREG? in --command, because attempting that would be tricky :D


More information about the ModemManager-devel mailing list