You can bet Trump Tower doesn’t have black dial phones anymore...most modern voice communications are digital, likely VoIP, and lawful intercepts (after a court order authroizes them) involve directing the cable company, phone company, ISP, etc to direct the communications data so authorized to the monitoring point. It’s more like forwarding email than some guy clipping alligator clips onto a punchdown block like you saw in the movies in the 60s. All it takes is software...and that pesky court order.
My late father was one of the men at the frame at Southern Bell in Miami tapping the lines way back when. That was their only job.
The NSA data mining comes to my mind.
http://www.popularmechanics.com/military/a9465/nsa-data-mining-how-it-works-15910146/