And also.... Radio Shack just entered the market with a cordless which uses frequency inversion. That's analog... Probably can be broken in less than a minute, even by amateurs who know how to solder. About 1986 or so, a certain state agency ordered some expensive walkie-talkies which were supposed to be secure against protesters with scanners. Guess what? Analog frequency inversion. And in fact, with a little practice, you can listen to inverted speech directly and make sense of it.