record voice at voice call

In my app, i want to perform the following scenario.

• User inputs a number and press 'Call' button
• The Call button will forward the call to the callee and start recording the voice of the caller (both task will be coded in the same button click event)
• When user presses the 'End' button, call and recording both will be stopped.
• Then the just recorded audio will be played (though it is one sided communication)

I want to make this app for iPhone 3. Is it possible to开发者_如何学Go make this app?

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I have thought of doing the same. You cannot record a call.