There are also a large number of Q codes that cover practically everything related to communication and also naval, aeronautic and rescue concerns. Today much of this isn't in use, but amateur radio operators use a subset of these routinely; a typical fast Morse code exchange is often composed almost entirely of Q codes and call signs.
I became aware of Q codes through their use in the book Seveneves. It provided a brief glimpse into a subculture that I've never had much contact with, and I ended up in a bit of a Wikipedia crawl.
I was lucky enough as a kid to inherit my grandfather's collection of old sci-fi books. I first became aware of Q codes through the short story "QRM Interplanetary" from 1942 (https://en.wikipedia.org/wiki/Venus_Equilateral).
I find it interesting that Q codes have changed so little over the last century. I have some ham radio friends who will use Q codes when talking face-to-face with each other, and the codes they use are basically the same ones from the original list.
I'm glad you commented. I was sitting here racking my brain, trying to remember what book I'd read that involved Q codes. Then I saw your comment, and it was indeed Seveneves.
[1] https://en.wikipedia.org/wiki/Q_code