Inside DCSNet, the FBI's Nationwide Eavesdropping Network
The surveillance system, called DCSNet, for Digital Collection System Network, connects FBI wiretapping rooms to switches controlled by traditional land-line operators, internet-telephony providers and cellular companies. It is far more intricately woven into the nation's telecom infrastructure than observers suspected.
"It's a "comprehensive wiretap system that intercepts wire-line phones, cellular phones, SMS and push-to-talk systems," says Steven Bellovin, a Columbia University computer science professor and longtime surveillance expert.
DCSNet is a suite of software that collects, sifts and stores phone numbers, phone calls and text messages. The system directly connects FBI wiretapping outposts around the country to a far-reaching private communications network.
Many of the details of the system and its full capabilities were redacted from the documents acquired by the Electronic Frontier Foundation, but they show that DCSNet includes at least three collection components, each running on Windows-based computers."
https://abcnews.go.com/Technology/story?id=3535528&page=1