Switching telecom servers (voice and IP) with CALEA access date back to the late 90s.
The Communications Assistance for Law Enforcement Act (CALEA) is a United States wiretapping law passed in 1994, during the presidency of Bill Clinton (Pub. L. No. 103-414, 108 Stat. 4279, codified at 47 USC 1001-1010).
CALEA's purpose is to enhance the ability of law enforcement and intelligence agencies to conduct electronic surveillance by requiring that telecommunications carriers and manufacturers of telecommunications equipment modify and design their equipment, facilities, and services to ensure that they have built-in surveillance capabilities, allowing federal agencies to monitor all telephone, broadband internet, and VoIP traffic in real-time.
The original reason for adopting CALEA was the Federal Bureau of Investigation's worry that increasing use of digital telephone exchange switches would make tapping phones at the phone company's central office harder and slower to execute, or in some cases impossible. Since the original requirement to add CALEA-compliant interfaces required phone companies to modify or replace hardware and software in their systems, U.S. Congress included funding for a limited time period to cover such network upgrades. CALEA was passed into law on October 25, 1994 and came into force on January 1, 1995.
In the years since CALEA was passed it has been greatly expanded to include all VoIP and broadband internet traffic. From 2004 to 2007 there was a 62 percent growth in the number of wiretaps performed under CALEA -- and more than 3,000 percent growth in interception of internet data such as email.
By 2007, the FBI had spent $39 million on its DCSNet system, which collects, stores, indexes, and analyzes communications data.