Modem and linux

Most of the modems are available with USB interface. USB interface is a good option as it supports high speed communication (35MBPS by USB 2.0).  There are certain good utilities available to troubleshoot devices connected to USB interface.
"lsusb" command lists USB devices with device id, vendor id and its description.
To see more details of devices such as driver in use for the device, device class, product name and manufacturer name, etc "usb-devices" is another good utility. Same details could be seen at /sys/kernel/debug/usb/devices.

Coming back to our purpose. Here we will be communicating to modem over serial interface. And so we need a USB to serial converter driver. Once serial data is available we will be seeing the network packet and so will be usb_wwan driver. From above command we can find 3G modem device's vendor id and product id. Lets go to make things working.

$modprobe usbserial vendor=0x<vendor id> product=<product id>

$modprobe usb_wwan option

Now driver lets go to network interface part.
Create node using ip link and bring it up with dhcp client to get ip address.


http://antipastohw.blogspot.in/2012/05/how-to-install-3g4g-cellular-modem-on.html
http://freedune.wordpress.com/2011/06/23/success-with-usb-3g-modems-on-android/

USB modem:

https://wiki.archlinux.org/index.php/USB_3G_Modem
http://www.draisberghof.de/usb_modeswitch/
http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?t=960

DHCP:

http://www.cyberciti.biz/faq/howto-linux-renew-dhcp-client-ip-address/