When iOS was released it came with support for connecting devices to the internet with personal hotspots. There was no longer any need to download software and tether devices. Whether the personal hotspot feature is enabled or disabled as standard depends very much on your carrier but this is essentially what makes your iPhone into a modem.
There are still a fair number of people who want to know how to use the iPhone as a modem so here are the step by step instructions:
- Go to your Home Screen and tap on Settings, and Personal Hotspots. If that option is not there it isn’t enabled so you will need to contact your carrier.
- Turn ON Personal Hotspots
- Connect iPhone to the computer with the USB cable
- If iTunes opens, close it. Go to Network Settings on your computer taskbar, you should see your iPhone listed as a Network Device
- Click on it to connect and you should now be able to access 3G connectivity on your device and it becomes your modem
This is a simple way of doing it; if you want to use it as a Wi-Fi device, simply activate Wi-Fi receivers on your computer and search for your device. It will be listed as a Network Device but you will have to supply a password to connect. The password can be found in Settings, andPersonal Hotspots on your device.
Note : If you cannot find Personal Hotspost in Settings , then go to Settings > General > Cellular > Personal Hotspots .
Source :- jailbreakmodo.com