Disable Data Usage

Apple iPhone - How disable my data usage?

On my iPhone3, How can I temporarily disable my data usage or Internet usage while I am not using it.

iPhone Tutorial
Change to airplane mode.

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Settings --> Airplane Mode (Turn On)

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Doesn't that also turn off the cellular (voice) radio?

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It turns off all connections to the internet.

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Airplane Mode turns off ALL of the radios, including voice. Not just data.

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And the GPS receiver.

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