In an input unit arrangement use is made of an input unit in combination with a mouse pad, which is provided with a position-coding pattern which codes coordinates for a plurality of positions on the mouse pad. Areas on the mouse pad are provided with subsets of the position-coding pattern which are dedicated to different functions. The input unit can be caused to optically read the position-coding pattern, whereupon the input unit arrangement decodes the positions that are coded locally on the mouse pad. By placing the input unit within the various areas on the mouse pad, a user can make the input unit arrangement carry out various functions, such as automatically switching from a mouse function, in which a cursor is controlled on a display on the basis of the decoded position, to an input function, in which information via the input unit is inputted into an electronic device, such as a computer, telephone, PDA etc. A method for controlling the input unit arrangement is also described, as is also use of an absolute position-coding pattern.