To get /dev/bandrich (so that you don't need to look for which /dev/ttyUSBx
is used by your dongle, and always use /dev/bandrich), add a udev file:

    /etc/udev/rules.d/bandrich.rules

containing one line:

    SUBSYSTEM=="tty", ENV{ID_VENDOR_ID}=="1a8d", ENV{ID_MODEL_ID}=="100d", ENV{ID_SERIAL_SHORT}=="357473040068155", ENV{ID_USB_INTERFACE_NUM}=="02", SYMLINK+="bandrich", MODE="0666"

Change vendor_id/model_id/serial/interface num to match yours.
Use lsusb -v to find values. For interface num, I'm not sure.
It corresponds to /dev/ttyUSBx (the x). I did:

    cat /dev/ttyUSBx

in one terminal, and:

    echo -e "AT\r" > /dev/ttyUSBx

in another one. And I took a number for which the first terminal displayed:

    AT
    OK

"02" (/dev/ttyUSB2) worked for me.
Here, I get, as result of lsusb -v:

    [SNIP]
    Bus 003 Device 009: ID 1a8d:100d BandRich, Inc. 4G LTE adapter
    Device Descriptor:
      bLength                18
      bDescriptorType         1
      bcdUSB               2.00
      bDeviceClass            0 (Defined at Interface level)
      bDeviceSubClass         0 
      bDeviceProtocol         0 
      bMaxPacketSize0        64
      idVendor           0x1a8d BandRich, Inc.
      idProduct          0x100d 4G LTE adapter
      bcdDevice            0.00
      iManufacturer          10 BandRich, Inc.
      iProduct                9 BandLuxe HSPA-LTE Adapter
      iSerial                11 357473040068155
    [SNIP]

You can also run:

    udevadm monitor

and unplug/replug the dongle. It will print some information.

The command:

    udevadm info --export-db

is also important to get the right identifier to put in ENV{}. (It also
gives the correct value.)

Here is extracted what I have for my dongle:

    P: /devices/pci0000:00/0000:00:1a.0/usb3/3-1/3-1.2/3-1.2:1.2/ttyUSB2/tty/ttyUSB2
    N: ttyUSB2
    S: bandrich
    S: serial/by-id/usb-BandRich__Inc._BandLuxe_HSPA-LTE_Adapter_357473040068155-if02-port0
    S: serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.2-port0
    E: DEVLINKS=/dev/bandrich /dev/serial/by-id/usb-BandRich__Inc._BandLuxe_HSPA-LTE_Adapter_357473040068155-if02-port0 /dev/serial/by-path/pci-0000:00:1a.0-usb-0:1.2:1.2-port0
    E: DEVNAME=/dev/ttyUSB2
    E: DEVPATH=/devices/pci0000:00/0000:00:1a.0/usb3/3-1/3-1.2/3-1.2:1.2/ttyUSB2/tty/ttyUSB2
    E: ID_BUS=usb
    E: ID_MM_CANDIDATE=1
    E: ID_MODEL=BandLuxe_HSPA-LTE_Adapter
    E: ID_MODEL_ENC=BandLuxe\x20HSPA-LTE\x20Adapter
    E: ID_MODEL_FROM_DATABASE=4G LTE adapter
    E: ID_MODEL_ID=100d
    E: ID_PATH=pci-0000:00:1a.0-usb-0:1.2:1.2
    E: ID_PATH_TAG=pci-0000_00_1a_0-usb-0_1_2_1_2
    E: ID_REVISION=0000
    E: ID_SERIAL=BandRich__Inc._BandLuxe_HSPA-LTE_Adapter_357473040068155
    E: ID_SERIAL_SHORT=357473040068155
    E: ID_TYPE=generic
    E: ID_USB_DRIVER=option
    E: ID_USB_INTERFACES=:ffffff:020600:0a0000:080650:
    E: ID_USB_INTERFACE_NUM=02
    E: ID_VENDOR=BandRich__Inc.
    E: ID_VENDOR_ENC=BandRich\x2c\x20Inc.
    E: ID_VENDOR_FROM_DATABASE=BandRich, Inc.
    E: ID_VENDOR_ID=1a8d
    E: MAJOR=188
    E: MINOR=2
    E: SUBSYSTEM=tty
    E: USEC_INITIALIZED=672068596

Note: you need to unplyg/replug your dongle for /dev/bandrich to appear.

Note: the mode 0666 is for everyone to access the dongle (no need for
      root privileges). If you prefer you can set it to 0600 (only root)
      or 0660 (root and group).

Then you need to configure pppd, to get correct 'route' information when
you run wvdial.

The file /etc/ppp/peers/wvdial should have the following content:

    noauth
    name wvdial
    usepeerdns
    defaultroute
    replacedefaultroute

The file wvdial.bandrich.conf has been created by copying some information
found on the Internet. Its content may not be fully correct. Adapt to your
situation. It seems to work here.
