The days of sitting in a basement, monitoring a line, using your Audiotechnics pocket 'buttset' with alligator clips is over. G-people now sit at computers in their air-conditioned offices. The process was simply explained, by arlene, in this post..."CALEA requires that communications providers allow law enforcement officials to be able to listen in on phone conversations and get information about those phone calls, but only when the law enforcement agency has gotten approval for the tap.
The law enforcement agency goes before a judge and presents reasons a wiretap is needed. If the judge approves, a legal document or order is delivered to the communications provider.
A specially authorized person at the communications provider logs in to a system specifically set up for CALEA-approved wiretaps. A number of systems are sold by various manufacturers, but all of them tap into the routers and switches that make up telecommunications networks.
All calls on the communications network are routed digitally over switches and routers. The system used for taps connects to a central point in the network, over which all communications travel.
The tapping system captures two primary pieces of information about the call—the actual voice transmission itself (often referred to as call content information [CCC]) and data associated with each call, such as the phone numbers at both ends of the call (often referred to as call associated data [CDC]).
The CCC and the CDC information are sent over special secure routers to the law enforcement agency.
The Federal Communications Commission has ruled that PC-to-PC calls, when a call is made directly from one computer to another over the Internet using Voice over Internet Protocol (VoIP) software such as Skype, is subject to CALEA. But as of this writing, no technical way has been devised to tap in to those calls." (source)
