emacs -- (Not X) Hexl-mode C-M does not work

[Joseph Hartmann <joeh@arakis.sugar-river.net>]

My "info" on emacs tells me after I do a M-x hexl-mode <enter>
C-M-x should be the way to insert a character in hex.  Does C-M-x
mean Control m (or Control M) followed by an "x" ?  Control-m or
Control M gives me a Carriage Return, not a prefix to a further
command.  This is emacs from the cheapbytes four-disk set of
debian; the emacs is version 19.34

Any suggestions will be appreciated.

joeh