No TTY-related discussion is complete without a reference to Linus Akesson's extremely lucid article on the whole thing, including what all the other interesting Ctrl+ characters do:

http://www.linusakesson.net/programming/tty/

...and the extensive previous HN discussion on it:

https://news.ycombinator.com/item?id=10631513

https://news.ycombinator.com/item?id=10064657

https://news.ycombinator.com/item?id=8094186

https://news.ycombinator.com/item?id=4544318

https://news.ycombinator.com/item?id=4062981

https://news.ycombinator.com/item?id=658155