Granted it took a bit more doing than nowadays, but the old phones had a mechanical ringer that is basically a microphone. No rewiring necessary. http://www.bug

Granted it took a bit more doing than nowadays, but the old phones had a mechanical ringer that is basically a microphone. No rewiring necessary. http://www.bugsweep.com/instrument.html http://www.bugsweep.com/instrument.html and https://www.schneier.com/blog/archives/2010/01/eavesdropping_i.html https://www.schneier.com/blog/archives/2010/01/eavesdropping...