Encrypted Cordless phones

[George A. Gleason]

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.