Photo by Ron Bosley

In the tap code, the letter x was used to break up sentences and the letter "c" replaced the letter "k." One of the more famous uses of the letter "c" for "k" was in the transmission "Joan Baez Succs," which POWs sent around the camp after the American antiwar activist's songs were played over the camp's public address system.

POW Vice Admiral James Stockdale, spoke of the code in the book In Love and War. He wrote about the pleasures of coming up with abbreviations, a necessity imposed by the time constraints on both the message giver and receiver. "Passing on abbreviations like conundrums got to be a kind of game... What would ST mean right after GN? 'Sleep tight,' of course. And DLTBBB? 'Don't let the bedbugs bite.'"