OT: Van Eck Phreaking was interesting reading indeed. I got interested as the Swedish phone system was very vulnerable to the use of tone generators, while making calls from phone booths in the 80’s… or so I’ve been told.
It wasn’t just the Swedish phone system. For a while you could do interesting things with a C-64 and the NA phone system. I could never have afforded to go check out BBS’s in Hawaii without some interesting things…