Another piece of elegance: by putting the uppercase letters in the block beginning at 0x40 (well, 0x41) it means that all the control codes at the start of the table line up with a letter (or one of a small set of other punctuation: @[\]^_), giving both a natural shorthand visual representation and a way to enter them with an early keyboard, by joining the pressing of the letter with... the Control key. Control-M (often written ^M) is carriage return because carriage return is 0x0D and M is 0x4D.