Mobile phone as a spy device

[Bhushan786]

I want to hear someone's voice from his mobile phone, whenever needed, without his knowledge. Is this possible? If yes, then how?

[Ryan]

this will require phone software modification like when someone calls you from a certain phone number the phone is autmaticly answered thus you will get the conversations happening but if you can do the programming good for you other than that am afraid that no one can help you here to do anything not legal