Signal quality

[José]

Thanks for the information.

On Tue, Mar 21, 2017 at 5:24 PM, Aleksander Morgado
<aleksander at aleksander.es> wrote:
> On Tue, Mar 21, 2017 at 5:04 PM, José <Joseddg92 at gmail.com> wrote:
>> ModemManager reports look like this:
>>
>> Status | lock: 'none'
>> | unlock retries: 'sim-pin (3), sim-pin2 (3), sim-puk (10), sim-puk2 (10)'
>> | state: 'connected'
>> | power state: 'on'
>> | access tech: 'hsdpa'
>> | signal quality: '38' (recent)
>>
>> I have some questinos about the signal quality quantity:
>>
>> * Which units does the 'signal quality' use?
>
> It's a percentage value (0-100). The "recent" flag tells us whether
> the signal was refreshed in the last 30s IIRC.
>
>> * Is it the same for any technology/modem?
>> * How does it relate to RSSI and dbm?
>
> Everywhere should be based on RSSI (dBm), scaled differently depending
> on how the value is retrieved from the modem.
>
> E.g. if given in dBm directly, scaled between -113dBm and -51dBm:
> https://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/mm-broadband-modem-qmi.c#n2627
>
> Or if already given scaled between 0 and 31 as in +CSQ:
> https://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/mm-broadband-modem.c#n1805
>
> Note that if you want "raw" technology-specific values, some modems
> (like QMI) provide the "extended" Signal interface, see:
> https://www.freedesktop.org/software/ModemManager/api/latest/gdbus-org.freedesktop.ModemManager1.Modem.Signal.html
>
> --
> Aleksander
> https://aleksander.es