1) Find Vendor and ProdID

Do

cat /proc/bus/usb/devices

In the generated list where Manufacturer is ZTE , Incorporated

Take Vendor and ProdID

eg. Vendor=19d2 ProdID=fffd

-You can also use lsusb to get entry with ONDA Communication S.p.A in format   a:b

eg  19d2:fffd

2) Load Module
modprobe usbserial vendor=0x19d2 product=0xfffd

After this step 3 interfaces /dev/ttyUSB* where *(0-2)
should be created .(if not then rmmod usbserial ->remove device->modprobe again->insert device )

3)Configure (Run in root mode)(NOT FOR FEDORA go to 6)
wvdialconf

4)Edit /etc/wvdial.conf
Add number eg. #777
Add your username and password in the fields.

5)Run
Ideally running wvdial should be enough.
(try ping google.com to check if you are connected)

6)However in fedora(and if above steps dont work for you) after modprobe
Go to System>Administration>Network>New>Modem>
In Modem Properties (Despite error)
change device to /dev/ttyUSB0
Modem Volume=low
->Forward
Phone number #777
Username and Password -as you have
Provider Name -any
->Forward
Save And activate
Try ping google.com