Hi Daenyth, On Thu, May 27, 2010 at 12:04:55PM -0400, Daenyth Blank wrote: > 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. I ran into the same difficulties on a project. The device is unreliable, I believe due to a driver compatibility issue (I think the device needs some special handling that cdc-acm does not provide). I did some debugging with it but lacked the time and expertise to finish the job. See this thread on linux-usb: http://kerneltrap.org/mailarchive/linux-usb/2010/2/19/6257991 Interesting that you are using the generic usb-serial driver. cdc-acm automatically bound to mine when I plugged it in. We ended up switching to the Sierra Wireless 598U 3G modem for our project. It works well with the option driver. Hope this helps. Thanks, Forest -- Forest Bond http://www.alittletooquiet.net http://www.pytagsfs.org
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