The Huawei e1550 3G dongle works beautifully with Linux. One annoyance is that it contains a CD image which confuses Linux. In order to make it work we just need to use usb_modeswitch. First plugin in the dongle, and then run the following command:
usb_modeswitch -v 0x12d1 -p 0x1001 -H
The argument to -p may be different for you: check the output of lsusb -v and find the product number in the output. Having got Linux to recognize the modem, you now need to configure wvdial. I use pay-as-you go on 3 UK. My wvdial.conf is as follows:
[Dialer Defaults] Init1 = ATZ Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 Stupid Mode = 1 Modem Type = Analog Modem ISDN = 0 Phone = *99# Username = username Password = password Modem = /dev/ttyUSB0 Dial Command = ATDT Baud = 9600 [Dialer three] Init2 = ATZ Init3 = ATQ0 V1 &D2 &C1 S0=0 +IFC=2,2 Init5 = AT+CGDCONT=1,"IP","3internet" ISDN = 0 Modem = /dev/ttyUSB0 Modem Type = Analog Modem Baud = 460800
Then run wvdial: wvdial -C wvdial.conf three and you should be connected!