These days 3G connections are becoming more and more popular, and one of the most popular modems, at least in Latin America is the Huawei 156, which is a USB HSDPA modem, it works automatically on Windows, also with Ubuntu (at least with the last version) but with Arch or Debian no, that is mainly because you do not install all the packages needed by default on these distros.
Well the only needed package is wvdial, so install it using your package manager tool (pacman, aptitude, apt-get, etc).
Once installed, edit the file
and make it look like this
[Dialer usb] ;Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 init1 = AT+CGDCONT=1,”IP”,”internet.tigo.bo” Modem Type = USB Modem Phone = *99# ISDN = 0 Username = ” “ Init1 = ATZ Password = ” ” Modem = /dev/ttyUSB0 Baud = 460800
Be sure to change it according to your needs, what you may need to change is internet.tigo.bo, change it for your provider APN, you may need to insert a username and password.
The above configuration works with Tigo Bolivia
To connect just open a terminal, and enter this command.
su -c "wvdial usb"
wait some seconds, and you will be connected to the internet, if you have the working configurations for other carriers along the world, copy them in the comments please, (comments will need approval to go online).