In the United States, the Communications Assistance for Law Enforcement Act (CALEA), on 1994 allows some services of the State which justify it, in particular the F.B.I, to carry out telephone tapping. But the technology also allows the transmission of voice by other means than the phone, especially via the Internet. However, wiretapping as a threat to individual liberties, only an Act may extend the powers of listening, on the phone on the modes of transmission of voice on the Internet. In this view, the F.B.I. is developing which is intended to become an extension of the Act of 1994.