ModemManager and Iridium 9522b

[Aleksander Morgado]

Hey Eric,

>
> Thanks for the quick reply!  I don't think that is possible.  I don't think
> it even likes 38400.  See below from the manual:
>
> 5.121 +IPR - Fixed DTE Rate (Revised Implementation)
>
> This implementation applies to the 9522A/9505A IS060xx and later and all
> software releases for
> 9522B, 9555(A), 9523, 9575, 9601, 9602, 9602-SB, and 9603.
>
> Set Command: +IPR=<rate>[,<autoflag>]
>
> Set the data rate at which the ISU will accept commands. The change in data
> rate takes effect after the
> result code (e.g., OK) is received by the DTE.
> <rate> takes the following values:
>
> 1 600 bps
> 2 1200 bps
> 3 2400 bps
> 4 4800 bps
> 5 9600 bps
> 6 19200 bps (default)
> 7 38400 bps
>
> Note: The use of 38400 bps with ISU models “9505” or “9522” is not
> recommended because the ISU
> can not handle this rate without losing some bits of data.
>

Ok, so then you'll need to manually specify the baudrate that is going
to be used to open the port. You can do this only in ModemManager git
master (not in 1.6.x or before), by specifying a custom udev rule
like, see:
https://lists.freedesktop.org/archives/modemmanager-devel/2017-March/004075.html

For a USB modem, it would be something like:
# vim /lib/udev/rules.d/77-mm-serial-iridium.rules
    ACTION!="add|change|move", GOTO="mm_serial_iridium_end"
    SUBSYSTEM=="tty", ATTRS{idVendor}=="1edd", ENV{ID_MM_TTY_BAUDRATE}="19200"
    LABEL="mm_serial_iridium_end"

For a serial modem, try to use the DEVPATH instead (as there's no
vid:pid to match), e.g.:
# vim /lib/udev/rules.d/77-mm-serial-iridium.rules
    ACTION!="add|change|move", GOTO="mm_serial_iridium_end"
    DEVPATH=="/devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.3/*",
ENV{ID_MM_TTY_BAUDRATE}="19200"
    LABEL="mm_serial_iridium_end"

Once the rule is in place:
$ sudo udevadm control --reload
$ sudo udevadm trigger

And restart ModemManager.

-- 
Aleksander
https://aleksander.es