Meaning of "signal quality" in output of "mmcli -m modem-id"

[Aleksander Morgado]

On Mon, Aug 15, 2016 at 3:43 PM, Ajay Garg <ajaygargnsit at gmail.com> wrote:
> Let's say modem-id is 0.
> So, in the output of "mmcli -m 0", we get an output for signal quality in
> the form ::
>
>                 signal quality: '71' (recent)
>
>
> What is this value?
> Is this related to the value returned by "AT+CSQ" in any manner?
>
>
> In particular, if the value returned by "AT+CSQ" is x, then the
> signal-strength in dbm is given by ::
>
>                     -113 + (2 * x)
>
> Is there a correlation for the signal-quality returned by "mmcli -m
> modem-id" (71 in this case)?

That would be 71%.

For +CSQ, we do this:
  quality = CLAMP (quality, 0, 31) * 100 / 31;

See https://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/mm-broadband-modem.c#n1837

-- 
Aleksander
https://aleksander.es