This explains the naff "Captain Crunch" section of Neal Stephenson's "Cryptonomicon". Not that you can get it where I live; it would have made sense to do a "Weetabix" section with the same theme.
It's funny, I know exactly what passage you mean and even though it's been many years since I read Cryptonomicon it's one of two specific passages I vividly remember reading and enjoying. This is even though I've never had Captain Crunch in my life.
(The other passage was the one about one of the characters using a computer while in prison and setting up a profusion of xterms scrolling through random files because he suspected he was being spied on using van Eck phreaking.)
Such a great book. Two of the big stand-outs to me have always been the bit about his ex-girlfriend doing a whole research project about his beard, and the phrase "anally copulating shopping carts" pops into my head every time Im at the super market.