sudo apt-get install wvdial

sudo gedit /etc/wvdial.conf

[Dialer a]
Modem Type = Analog Modem
Phone = *99#
ISDN = 0
Baud = 460800
Username = " "
Password = " "
Modem = /dev/ttyUSB0
Init1 = ATZ
Init2 = at+cgdcont=1,"ip","your apn"
Stupid Mode = 1

wvdial a