-@item -O box[@var{line-type}]=@var{box-chars}
-Sets the characters used for lines in tables. @var{line-type} is a
-4-digit number that indicates the type of line to change, in the order
-`right', `bottom', `left', `top'. Each digit is 0 for ``no line'', 1
-for a single line, and 2 for a double line. @var{box-chars} is the
-character or string of characters to use for this type of line.
-
-For example, @code{box[0101]="|"} sets @samp{|} as the character to
-use for a single-width vertical line, and @code{box[1100]="\xda"} sets
-@samp{"\xda"}, which on MS-DOS is suitable for the top-left corner of
-a box, as the character for the intersection of two single-width
-lines, one each from the right and bottom.
-
-The defaults use @samp{-}, @samp{|}, and @samp{+} for single-width
-lines and @samp{=} and @samp{#} for double-width lines.
-
-@item -O init=@var{init-string}
-If set, this string is written at the beginning of each output file.
-It can be used to initialize device features, e.g.@: to enable VT100
-line-drawing characters.
+@item @option{-O box=@{ascii|unicode@}}
+Sets the characters used for lines in tables.
+If set to
+@code{ascii} the characters @samp{-}, @samp{|}, and @samp{+} for single-width
+lines and @samp{=} and @samp{#} for double-width lines are used.
+If set to @code{unicode} then Unicode box drawing characters will be used.
+The default is @code{unicode} if the locale's character encoding is "UTF-8"
+or @code{ascii} otherwise.