@var{num} were 0, i.e., it uses the terminal's default color support
mode.
@end table
-If @var{mode} is omitted, it defaults to @var{ansi8}. This support is
-dynamic: the current mode is available via the @code{tty-color-mode}
-frame parameter, and it can be changed by modifying that frame parameter.
-This means you can also specify the initial value via
+
+This option has no effect on MS-Windows and MS-DOS.
+
+@cindex colors on character terminal, changing during session
+@cindex character terminal, change color mode
+@vindex tty-color-mode@r{, frame parameter}
+If @var{mode} is omitted, it defaults to @var{ansi8}.
+
+The color mode can be changed dynamically during a running Emacs
+session: the current mode is available via the @code{tty-color-mode}
+frame parameter, and it can be changed by modifying that frame
+parameter.@footnote{
+This does not work on MS-Windows and MS-DOS text-mode terminals.
+} This means you can also specify the initial value via
@code{default-frame-alist} instead of the command-line option.
@end table
If the parameter's value is a symbol, it specifies a number through
the value of @code{tty-color-mode-alist}, and the associated number is
-used instead. This parameter supports dynamic changes.
+used instead. This parameter supports dynamic changes during a running
+Emacs session (but not on MS-Windows and MS-DOS).
@vindex screen-gamma@r{, a frame parameter}
@item screen-gamma
(push '(tty-color-mode . no) default-frame-alist)
@end lisp
-To disable tty color support in the @emph{current} frame you can run:
+@noindent
+To disable tty color support in the @emph{current} frame you can
+evaluate:
@lisp
(set-frame-parameter nil 'tty-color-mode 'no)
@end lisp
+Note that this currently doesn't work on MS-Windows and MS-DOS, whose
+text-mode terminals always use the fixed number of 16 text colors.
+
The command @kbd{M-x list-colors-display} pops up a window which
exhibits all the colors Emacs knows about on the current display.