I had just installed the same modem at my friend's house around 3 days ago.
The setup needs to be something like this:
First of all, ensure that everything is updated and wvdial is installed.
Then insert the modem.
On the terminal, type lsusb which should give you a line like 19d2:fff1 ONDA Commnunications
If its not there then you will need usb_modeswitch application. I don't have much idea about that, but Google may help you.
Then if you see the same string in the lsusb output, run wvdialconf as root.
It will show some output, etc. and write the configuration to /etc/wvdial.conf, if wvdialconf hangs or is not able to write configuration, put this in /etc/wvdial.conf:
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Modem Type = Analog Modem
Baud = 460800
New PPPD = yes
Modem = /dev/ttyUSB0
ISDN = 0
Phone = #777
Password = XXXXXXXXXX
Username = XXXXXXXXXX
PPPP Path = /usr/sbin/pppd
New PPPD = 1
Stupid Mode = 1
Tonline = 0
Replace Username and Password as given to you.
Then as root run wvdial, it should connect!
I read somewhere that the modem needs to be in hybrid mode, so you will first need to install it in windows.
Also wvdial may output weird characters if the signal is weak. So just check that red light does not blink on the modem (excluding first two blinks), or change the postion of the modem/computer so that you get green/blue whatever light, but NOT red.