Re: SARA-R4 unreliable LTE-M connection problem

Connection can be established, I see data on the modems RX line, but nothing
on the TX line, which means the host sends data to the modem, but gets back

Can this be a problem with the baudrate? I mean it's a classical serial UART,
so I would assume baudrates of host and modem must match. In AT command mode
the baudrate is 115200 and ModemManager can successfuly send AT commands and
receives reponses. Is it possible NetworkManager and/or pppd change this

Have you tried to set the ID_MM_TTY_FLOW_CONTROL udev tag in the TTY
port so that flow control settings are applied by ModemManager before
the connection is started? E.g. ID_MM_TTY_FLOW_CONTROL set to
"rts-cts" or to "xon-xoff"

Also, if using 115200, have you set ID_MM_TTY_BAUDRATE to 115200 as
well as a udev tag in the TTY port? The default in MM is 57600 really.


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]