emacs -Q
The character range (128 .
4194303) is bound to `self-insert-command'.
(single-key-description 128)
gives "\200"
(single-key-description 4194303) gives "\377"
However, in the former case,
"\200" is a string with one character,
\200. In the latter case, "\377" is a
string with four characters, \,
3, 7, and 7.
In GNU Emacs 23.1.1
(i386-mingw-nt5.1.2600)
of 2009-07-29 on SOFT-MJASON
Windowing
system distributor `Microsoft Corp.', version 5.1.2600
configured using
`configure --with-gcc (4.4)'