Setting up 3G dongle/USB Modems for linux

In some places, 3G USB modems might be only way to connect our servers to internet. Below is a guideline to install and use 3G dongles in linux.

Install wvdial to be used for dialing 3G modem

yum install wvdial

Now create a configuration file for wvdial in ‘/etc/wvdial.conf'

vi /etc/wvdial.conf

Dialer Defaults

[Dialer Defaults]
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2
Init3 = AT+CGDCONT=1,"IP”,"<APN of Internet provider>"
Stupid Mode = 1
Modem Type = USB Modem
New PPPD = no
Modem = /dev/ttyUSB2
ISDN = 0
Auto Reconnect = 1
Phone = *99#
Username = <Provider username>
Password = <Provider password>
Baud = 460800
Carrier Check = no

Install required libraries and tools.

yum install tcl usbutils libusb1-devel

Download usb_modeswitch and usb_modeswitch_data

Download using wget command

wget http://www.draisberghof.de/usb_modeswitch/usb-modeswitch-data-20151101.tar.bz2 #or latest
wget http://www.draisberghof.de/usb_modeswitch/usb-modeswitch-2.2.6.tar.bz2  #or latest

Extract and install

tar xvfj usb-modewitch-2.2.6.tar.bz2
tar xvfj usb-modewitch-data-20151101.tar.bz2

cd usb-modewitch-2.2.6
make install

cd usb-modewitch-data-20151101
make install

usb_modeswitch creates some udev rules to automatically change the mode of 3G dongle to act as usb_modem

Now plug in your 3G dongle, it should automatically be detected.

     dmesg | grep tty   # should show something like 'GSM modem (1-port) converter now attached to ttyUSB0'
     sudo wvdial &

Now this should start dialing via 3G modem, and internet should be started.

For more info - http://www.draisberghof.de/usb_modeswitch/