\newlength{\myheight}
\setlength{\myheight}{1cm}
\newlength{\myheighta}
\setlength{\myheighta}{2cm}
    \begin{tabular}{|l|r|c|c|r|c|}
     \hline
     \multicolumn{2}{|c|}{{\small Module}}&{\small Sensor}&{\small Oct 2010}&{\small Dec 2012} & {\small Ratio} \\ \cline{3-5}
     \multicolumn{2}{|c|}{type}  & maker& {\small ENC [e]} & {\small ENC [e]} &  $\frac{2012}{2010}$ \\ \hline
     \multicolumn{2}{|l|}{{\small Endcap outer}} & {\small HPK}& 1567 & 1552 & 0.99 \\ \hline

     \parbox[c][\myheight][c]{0cm}{Height} & test & tesT & 1567 & 1552 & 0.99 \\ \hline

     \parbox[c][\myheighta][t]{6cm}{Height} & t & tesT & 1567 & 1552 & 0.99 \\ \hline

     \multicolumn{2}{|l|}{\parbox[c][1.5cm][c]{0cm}{Height}} &T & 1567 & 1552 & 0.99 \\ \hline
    \end{tabular}


\parbox[position][height][inner-pos]{width}{text} 
---------------------------
http://herbert.the-little-red-haired-girl.org/html/latex2e/$5cparbox.html

2.17.17: \parbox

\parbox[position][height][inner-pos]{width}{text} 

A parbox is a box whose contents are created in paragraph mode. The \parbox has two mandatory arguments: 
?width - specifies the width of the parbox, and 
?text - the text that goes inside the parbox. 

LaTeX will position a parbox so its centre lines up with the centre of the text line. The optional position argument allows you to line up either the top or bottom line in the parbox (default is top). 

If the height argument is not given, the box will have the natural height of the text. 

The inner-pos argument controls the placement of the text inside the box. If it is not specified, position is used. 
?t --- text is placed at the top of the box. 
?c --- text is centred in the box. 
?b --- text is placed at the bottom of the box. 
?s --- stretch vertically. The text must contain vertically stretchable space for this to work.