\setuplayout
 [height=middle,
  width=middle,
  backspace=3cm,
  leftmargin=1cm,
  rightmargin=2cm]

\setuppagenumbering
  [alternative=doublesided]

\showframe

\starttext

    \dorecurse {200} {
        \ininner{I}%
        \inouter{O}%
        test #1\par
    }

    \page

    \dorecurse {10} {
        \ininner{I I I I I I I I I I I I}%
        \inouter{O O O O O O O O O O O O}%
        \input tufte \par
    }

\stoptext
