ZTE MF833V: connection issues due to signal quality not updated
Hi,
I tried to make a ZTE MF833V modem work with Modem Manager 1.14.8 and I encountered connections issues. Each time I try to establish one, an error occurs about not being able to update signal quality, leading to serial timeouts and connection close.
Jan 11 13:01:44.554383 tap-00005F22 ModemManager[1299]: <debug> [1610370104.554353] [modem0] signal quality value not updated in 60s, marking as not being recent
Jan 11 13:01:44.554449 tap-00005F22 ModemManager[1299]: <debug> [1610370104.554438] [modem0/ttyUSB2/at] device open count is 6 (open)
Jan 11 13:01:44.554469 tap-00005F22 ModemManager[1299]: <debug> [1610370104.554462] [modem0/ttyUSB2/at] device open count is 5 (close)
Jan 11 13:01:44.554577 tap-00005F22 ModemManager[1299]: <debug> [1610370104.554567] [modem0/ttyUSB2/at] --> 'AT+CCLK?<CR>'
Jan 11 13:01:47.553664 tap-00005F22 ModemManager[1299]: <debug> [1610370107.553597] [modem0] couldn't load network timezone: Serial command timed out
Jan 11 13:01:47.553710 tap-00005F22 ModemManager[1299]: <warn> [1610370107.553685] [modem0] couldn't load network timezone from the current network
Jan 11 13:01:47.553732 tap-00005F22 ModemManager[1299]: <debug> [1610370107.553718] [modem0/ttyUSB2/at] device open count is 4 (close)
Jan 11 13:01:47.553773 tap-00005F22 ModemManager[1299]: <warn> [1610370107.553756] [modem0] port ttyUSB2 timed out 2 consecutive times
Jan 11 13:01:47.553809 tap-00005F22 ModemManager[1299]: <debug> [1610370107.553798] [modem0/ttyUSB2/at] --> 'AT+CIND?<CR>'
Jan 11 13:01:50.360706 tap-00005F22 ModemManager[1299]: <debug> [1610370110.360678] [modem0/ttyUSB1/at] <-- '<CR><LF>+CIEV: 1,3<CR><LF>'
Jan 11 13:01:52.553059 tap-00005F22 ModemManager[1299]: <debug> [1610370112.553029] [modem0/ttyUSB2/at] device open count is 5 (open)
Jan 11 13:01:52.553088 tap-00005F22 ModemManager[1299]: <debug> [1610370112.553078] [modem0/ttyUSB2/at] device open count is 4 (close)
Jan 11 13:01:52.553115 tap-00005F22 ModemManager[1299]: <warn> [1610370112.553106] [modem0] port ttyUSB2 timed out 3 consecutive times
Jan 11 13:01:52.553137 tap-00005F22 ModemManager[1299]: <debug> [1610370112.553129] [modem0/ttyUSB2/at] --> 'AT+CEER<CR>'
Jan 11 13:01:53.565077 tap-00005F22 ModemManager[1299]: <debug> [1610370113.565054] [modem0/ttyUSB1/at] <-- '<CR><LF>+CIEV: 1,4<CR><LF>'
Jan 11 13:01:55.552005 tap-00005F22 ModemManager[1299]: <debug> [1610370115.551961] [modem0/ttyUSB2/at] device open count is 3 (close)
Jan 11 13:01:55.552036 tap-00005F22 ModemManager[1299]: <warn> [1610370115.552025] [modem0/bearer0] connection attempt #1 failed: Serial command timed out
Jan 11 13:01:55.552180 tap-00005F22 ModemManager[1299]: <info> [1610370115.552163] [modem0] state changed (connecting -> registered)
Jan 11 13:01:55.552613 tap-00005F22 ModemManager[1299]: <info> [1610370115.552597] [modem0/bearer0] connection #1 finished: duration 0s, tx: 0 bytes, rx :0 bytes
The behaviour is systematic with this model.
When looking for a workaround and/or a fix, I found that, if I deactivate the modem indicator support with MM_BROADBAND_MODEM_INDICATORS_DISABLED
property in the ZTE plugin, the errors do not occur and the PPP connection is properly established.
The AT command list document I was provided with the model do not mention the +CIND/CMER/CIEV support whereas +CSQ is in it.
As a fix, it seems overkill and I don't have other ZTE models to check if they have the same behaviour. Is there any better solution than this one ?
debug logs: ZTE_MF833V.log ZTE_MF833V_with_disabled_modem_indicators.log
lsusb output: zte_lsusb.log