Looking for advice about using NM with a Sprint U301 modem

[Daenyth Blank <daenyth gmail com>]

Hi all,

I'm trying to find out some information regarding the Sprint U301 3G
modem. Our use case for it is that it will be attached to an embedded
machine running ubuntu with networkmanager, in addition to our
software. I've been trying to get this modem to connect reliably and
am having some issues with it. I've added a udev rule so that the
usbserial driver is given the correct vendor/product information, and
it connects automatically on boot, but not reliably. Some boots it
does not connect at all and won't until I reboot. Sometimes it
disconnects while the machine is running. If it disconnects either by
itself or from deactivating the connection, it will not connect again
and needs a reboot. The nm/mm logs say that serial requests are timing
out when it's in the non-connected state. I haven't been able to
recover from the disconnected state with anything about a reboot.

Is there anything we can do with this device to increase reliability?
Failing that, can you recommend a usb Sprint 3G modem that will be
more reliable? If there are none, do you have any recommendations for
any brand of 3G modem that will work well in this situation? The boxes
will be deployed where manual access is not easy, so it needs to be
able to connect and recover from disconnections automatically, or at
least in a way that can be scripted easily.

Thanks,
-- Daenyth