seriously, i'm offering $50 to anyone who can solve the problem i'm about to describe. i mentioned it briefly to a few people last night but i'm still fighting with it, so here it is. briefly, i can use a huawei E367 3G usb dongle: http://www.huaweidevice.com.eg/Product-Description/Data-cards-E367.php to connect to rogers from my ubuntu laptop using PPP, and simultaneously use a utility like "comgt" to query the device, as in: $ comgt info [general info] $ comgt sig [signal strength] and so on. works perfectly. on the other hand, i'm trying to do *exactly* the same thing on an embedded arm system and the only glitch is that, once i bring up PPP, i lose the ability to query the modem. and now, to details. first, let's talk about my laptop -- current ubuntu, 3.7.0 kernel, and so on. in short, current software. when i plug in the dongle, udev responds by creating three new device files: /dev/ttyUSB[012]. on my laptop, USB0 will be used by PPP itself, while USB2 is the out-of-band admin channel with which you'd query the modem even while PPP was running. so after i plug in the modem, i get the device files, i run a script that uses minicom to set the properties of USB0, then run "pppd" to start on /dev/ttyUSB0. works fine and, all this time, i can use /dev/ttyUSB2 to prod the modem and get information about it. on to the arm system. everything there works almost the same way. i plug in the modem, i get the same three device files, and i can immediately query the modem (on /dev/ttyUSB2) as before. i run the USB0 config script to prepare USB0 for PPP, that also works, and again, querying the modem still works. however, once i run pppd and PPP starts to work, /dev/ttyUSB2 simply stops responding. PPP will run just fine but, somehow, the act of starting PPP on /dev/ttyUSB0 shuts down /dev/ttyUSB2. a number of differences with the arm system: * different architecture (obviously) * older kernel (2.6.37) * older udev and udev rules it would be one thing if it simply failed completely. but as you can see, the flaw is fairly subtle -- the act of starting PPP shuts down the modem's admin port. that's it, that's the only drawback i can see. i'm currently looking at the usb-modeswitch rules, i can see from this page: http://linux.die.net/man/1/usb_modeswitch that there's an option "-H, --huawei-mode" but it doesn't appear to come into play anywhere. if anyone has run across this before, i'm open to suggestions. the problem is *entirely* reproducible. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================