[Symbiote]

Type

   man ascii

and notice what is 0x40 less than the capital letter.

H is 0x48, backspace is 0x08. ^H is the same as backspace.

I is 0x49, tab is 0x09, ^I is the tab sequence.

Now you know why Windows \r in text file show up as ^M in vi and Emacs.

^D is ASCII 0x04, "EOT (end of transmission)". That's why you use that to end input.

^C is ASCII 0x03, whose name is "ETX (end of text)". That seems a reasonable choice.