How do I put my iPhone 3GS into DFU / recovery mode?

How do I put my iPhone 3GS into DFU / recovery mode?

To put your iPhone into recovery (DFU) mode:

1. Make sure the iPhone is off and unplugged from your computer.
2. Hold down the home button.
3. While holding down the home button plug the iPhone into your computer.
4. Continue to hold the home button until the Apple logo disappears and the iTunes logo appears.
5. Now you can let go of the home button.
6. iTunes will say it has detected an iPhone in recovery mode.

Comments

You can follow these steps :

Press and hold the power button that is present on the top edge of the iPhone and along with that press home buttonfor at least 15 seconds

Wait till the iphone device turns off and then release the power and home button. It could take around fifteen seconds to power off.
Turn iPhone On by pressing iphone button. And hwen the iphone reboots, it will not be in recovery mode.
And for More info visit :
http://bit.do/Put-iPhone-Into-DFU-Mode

how to put in dfu mode not in recovery mode??????