To be CALEA-compliant, USA telecommunications providers must install new hardware and software, as well as modify old equipment so it doesn't interfere with any law enforcement agency's ability to perform real-time surveillance of any telephone or Internet traffic.
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Originally CALEA only granted the ability to wiretap digital telephone networks, but in 2004, the United States Department of Justice (DOJ), Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), Federal Bureau of Investigation (FBI), and Drug Enforcement Administration (DEA) filed a joint petition with the Federal Communications Commission (FCC) to expand their powers to include the ability to monitor VoIP and broadband internet communications -- so that they could monitor Web traffic as well as phone calls.
http://en.wikipedia.org/wiki/Communications_Assistance_for_Law_Enforcement_ActCommunications equipment must be designed with built-in ability to identify traffic flows and intercept the signals in order to comply with CALEA. Other governments have requirements similar to those of the United States.