3G modem showing up 2 x as /dev/cua?

  • I have an USB 3 modem (Huawei E353-u2) on 2.0.2, in the PPP configuration (Link Type PPP) it shows up twice:


    1. Why are there 2 devices? Is one of them maybe the usb mass storage of the stick? If yes, shouldn't that be automatically hidden in the PPP screen?
    2. On the OS level (shell), how can I find out which of those 2 devices is the "real modem" / to what /dev/cuaUx.y is mapped?

    Thanks for any hint :-)

  • Netgate Administrator

    Both of those devices are USB serial ports. /dev/cua* devices are serial ports, the capital 'U' in the name implies it is USB connected. 3G modems often appear as more than one serial port, usually one is available for modem connection and others provide diagnostic output such as signal strength etc.
    You can just try each of them via the pfSense gui to find out which it is. Alternatively you can talk to the device with a terminal emulator, the real modem will respond to AT commands. E.g.

    cu -l /dev/cuaU0.0 -s 115200

    You may have to try several speeds or other variations on that command.  ;)


  • Thank you for your reply! Using a baud rate of "115200" works. It hangs after trying AT multiple times though. Also both devices return OK for the AT command. Only one of the devices however gives a output of BOOT and some numbers (repeated again and again).
    Just wondering, isn't it somehow possible to map the output of "usbconfig list" to the /dev/dua* devices?

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