Sierra Wireless EM7355 - can't find serial port for PPP

  • Hi Folks,

    I picked up an EM7355 along with an M.2 to Mini PCI-E Adapter (B type, with SIM slot) to use with a Gigabyte GA-J1900N-D3V.  So far I'm able to see that the card is installed, so I've followed the instructions in the "Configuring 3G modems" wiki entry, but no go – it doesn't look like the serial ports are being picked up by pfSense.

    From other threads (e.g. I'm seeing that I might need some firmware flashing before I'm able to move forward.  I have no other machine with a mini pci-e slot available to me right now, so before I temporarily install Linux or Windows on the pfSense box, I'm wondering if there's any other way I can approach this.  Here's what's listed when probing USB:

    [2.3-RELEASE][]/root: usbconfig -u 0 -a 3 dump_device_desc
    ugen0.3: <sierra wireless="" em7355="" qualcomm="" gobitm="" 4g="" ltehspa+evdo="" sierra="" wireless,="" incorporated="">, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (2mA)
      bLength = 0x0012
      bDescriptorType = 0x0001
      bcdUSB = 0x0200
      bDeviceClass = 0x0000  <probed by="" interface="" class="">bDeviceSubClass = 0x0000
      bDeviceProtocol = 0x0000
      bMaxPacketSize0 = 0x0040
      idVendor = 0x1199
      idProduct = 0x901e
      bcdDevice = 0x0000
      iManufacturer = 0x0001  <sierra wireless,="" incorporated="">iProduct = 0x0002  <sierra wireless="" em7355="" qualcomm="" gobi(tm)="" 4g="" lte="" hspa+="" evdo="">iSerialNumber = 0x0000  <no string="">bNumConfigurations = 0x0001</no></sierra></sierra></probed></sierra> 

    I'm seeing cuau0 and cuau1 under /dev, but these are likely the two on-board COM ports from the motherboard.  If no serial ports associated with the EM7355 are shown, I'm assuming this means pfSense isn't loading the driver because it doesn't like the PID of 0x901e.  Do I have any way out of this, short of getting another OS involved?

    Thanks for any help anyone can provide!

  • I've been playing with this off and on for the past month+, and I'm nowhere closer to success. The device I started out with (0x1199/0x901e) was not recognized by pfSense, nor Centos 7.  Windows 7 was no better – 0x901e is not a popular variant of this card, and no matter what drivers I used (starting with Sierra Wireless, progressing to shady 3rd party 'driver manager' sites, and even modifying inf files of the official SW drivers), I ended up with the card not actually working.  Plus, at no point was there a working serial port provided to any of the OSes, so even if I wanted to issue AT commands to change PIDs, I was SOL.  Because this device was an AliExpress import of questionable origin, I figured I should cut my losses and find another EM7355.

    Next step: I obtained a less "exotic" variant of the card, a Lenovo part (FRU04X6038) which gave me 0x1199/0x901f.  No better under pfSense (now at 2.3.1_1) or Centos (neither picked it up in a way which I could talk to it, serial or otherwise), though under Windows (10) the drivers obtained from Sierra Wireless picked up the card without having to modify any inf files.  Still, the COM ports it did present didn't actually respond to any commands (trying multiple speeds, etc.) nor did the Sierra Wireless Watcher software pick up the card.  I next tried it in a Lenovo laptop (Win 7) in which the card was supposedly compatible.  The first time around, the laptop booted up, I installed Lenovo's drivers, and things seemed like they were going in the right direction.  However, upon a required reboot (Lenovo Access Connection software), the laptop refused to boot due to what it claimed was an incompatible card.  No idea why it was okay with it at first, but now it was complaining.  VID/PID seemed to be the same.

    So, I'm pulling my hair out here!  I'd be hugely grateful if someone had some experience with these cards and could give me some pointers on where to turn next.  Sierra Wireless doesn't seem to pay attention to end-users.

    Ultimately, I'm looking for a T-Mobile (USA, LTE bands 2 and 4) compatible device which I can connect to my pfSense box, either via Mini PCI Express or USB.  I don't want to spend hundreds on a Cradlepoint (or similar) box -- I'd be paying for a router (which I'd rather be pfSense) when all I need is an interface to a modem.  If you know of a device that would accomplish this, hopefully under $100, I'd throw these EM7355's out the window in a heartbeat.

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