Unknown behaviour when signal quality is poor
alexvega48 at gmail.com
Tue Jan 26 17:07:32 UTC 2021
I am finding a unexpected behaviour and I would like to know how does the
ModemManager work in situations like this one, when the modem has no signal
at all or the signal is quite poor:
<debug> [1607682864.814360] Received notification (service 'basic-connect',
<debug> [1607682864.814379] Signal state indication: 6 --> 19%
<debug> [1607682864.814532] Modem /org/freedesktop/ModemManager1/Modem/0:
signal quality updated (19)
<debug> [1607682866.172436] (ttyACM1): --> 7e 00 78 f0 7e
<debug> [1607682866.172535] (ttyACM0): --> 7e 00 78 f0 7e
[/dev/cdc-wdm0] Received message...
>>>>>> length = 64
>>>>>> data =
[/dev/cdc-wdm0] Received message (translated)...
>>>>>> length = 64
>>>>>> type = indicate-status (0x80000007)
>>>>>> transaction = 0
>>>>>> Fragment header:
>>>>>> total = 1
>>>>>> current = 0
>>>>>> service = 'basic-connect' (a289cc33-bcbb-8b4f-b6b0-133ec2aae6df)
>>>>>> cid = 'signal-state' (0x0000000b)
>>>>>> Rssi = '0'
>>>>>> ErrorRate = '99'
>>>>>> SignalStrengthInterval = '5'
>>>>>> RssiThreshold = '2'
>>>>>> ErrorRateThreshold = '4294967295'
<debug> [1607682867.822380] Received notification (service 'basic-connect',
<debug> [1607682867.822400] Signal state indication: 0 --> 0%
<debug> [1607682867.822557] Modem /org/freedesktop/ModemManager1/Modem/0:
signal quality updated (0)
- The modem does not seem to transition from the "*connected*" state to the
"*registered*" state , or at least I cannot see it in the logs (attached
in a previous mail). It remains as *state: connected.*
What is the expected behaviour here?
*- *What does the ModemManager do in these cases where the modem is
connected to the ISP but has really really low signal (i.e. signal state
0) ? When does the Modem Manager consider the modem disconnected ?
El lun, 14 dic 2020 a las 15:31, Alejandro Vega (<alexvega48 at gmail.com>)
> Attached logs of the found behaviour and status of the modem before the
> signal loss.
> Kind regards,
> El lun, 14 dic 2020 a las 10:07, Alejandro Vega (<alexvega48 at gmail.com>)
>> Attached logs
>> El lun, 14 dic 2020 a las 10:05, Alejandro Vega (<alexvega48 at gmail.com>)
>>> Hello !
>>> First of all, thanks in advance for your time and dedication. I am
>>> developing an application making use of libmm-glib high level API and
>>> running under *ModemManager version 1.10.6*.
>>> I am currently experiencing some trouble and I would like to know if the
>>> behaviour of the Modem + ModemManager system is the expected one or there
>>> is some kind of malfunction somewhere.
>>> The problem is that we are experiencing some signal problems around an
>>> specific area (particularly, every time that a bus passes by an area where
>>> the signal strength is poor). I *attach *the *ModemManager debug logs*
>>> of the outward and return journey only when the bus is passing by this
>>> Regarding this, we have the following doubts:
>>> - Is the behaviour of the ModemManager the expected one ? Our
>>> application queries the ModemManager to scan for devices periodically, can
>>> this cause an unexpected behaviour ?
>>> - We are using a "global" M2M card which should be able to use
>>> different network operators. Is the ModemManager able to switch between
>>> operators in order to achieve better signal strengths ? If this is not the
>>> case, in order to achieve this, how would we need to proceed?
>>> Once again,thank you very much.
>>> Kind regards,
>>> Alejandro Vega
>> Un saludo.
>> Alejandro Vega
> Un saludo.
> Alejandro Vega
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